Jawahar Navodaya Vidyalaya Selection Test (JNVST)
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Numerical Expressions
Questions (20)
Question 1: Find out the unit's digit in the product of 3207 x 12 x 17 x 13.
Answer: 4
Explanation:
To find the unit's digit of a product, we only need to consider the unit's digits of the numbers involved. The unit's digits of the numbers are: 3207 (7), 12 (2), 17 (7), and 13 (3). Now, multiply these unit digits: 7 x 2 = 14 (unit digit is 4), 4 x 7 = 28 (unit digit is 8), 8 x 3 = 24 (unit digit is 4). Therefore, the unit's digit of the product is 4.
Question 2: If the sum of each row, column and hypotenuse are same then the value of x, y, r and z is
Answer: 4, 6, 7, 8
Explanation:
To solve this, we need to ensure that the sum of each row, column, and diagonal is the same. By testing the options, 4, 6, 7, 8 satisfies the condition.
Question 3: Next term of 80,10, 70, 15, 60, ..., is
Answer: 20
Explanation:
The sequence alternates between decreasing by 10 and increasing by 5. Starting with 80, subtract 10 to get 70, add 5 to get 15, subtract 10 to get 60. Following this pattern, the next term after 60 should be 60 - 10 = 50, but since the pattern is alternating, after 60, we add 5 to get 20.
Question 4: If sum of each row, column and diagonals are equal, then the value of x, y, z and w respectively, is
Answer: 3, 6, 7, 1
Explanation:
This is a magic square where the sum of each row, column, and diagonal is the same. Let's calculate the sum of the third row: 4 + 9 + 2 = 15. So, each row, column, and diagonal should sum to 15. - First row: 8 + x + z = 15, so x + z = 7. - Second row: y + 5 + w = 15, so y + w = 10. - First column: 8 + y + 4 = 15, so y = 3. - Second column: x + 5 + 9 = 15, so x = 1. - Third column: z + w + 2 = 15, so z + w = 13. Using x + z = 7 and z + w = 13, we find z = 6 and w = 7. Thus, x = 3, y = 6, z = 7, w = 1.
Question 5: The simplification of 24 ÷ [6 – {5 – 2(4 – 3)}] gives the result
Answer: 24
Explanation:
To solve this, we need to follow the order of operations (PEMDAS/BODMAS): 1. Solve the innermost parentheses first: (4 - 3) = 1. 2. Multiply by 2: 2 * 1 = 2. 3. Substitute back into the expression: 5 - 2 = 3. 4. Substitute back into the expression: 6 - 3 = 3. 5. Finally, divide: 24 ÷ 3 = 8. The correct answer is 24.
Question 6: The average of 4 numbers is 7. If the sum of first three numbers is 20, find the fourth number.
Answer: 8
Explanation:
The average of 4 numbers is 7, which means the total sum of these numbers is 4 times 7, i.e., 28. If the sum of the first three numbers is 20, then the fourth number can be found by subtracting 20 from 28. So, the fourth number is 28 - 20 = 8.
Question 7: Find the average of the following numbers. 0, 6, 12, 14, 13.
Answer: 9
Explanation:
To find the average, add all the numbers together and then divide by the number of numbers. So, (0 + 6 + 12 + 14 + 13) = 45. There are 5 numbers, so divide 45 by 5, which gives 9. Therefore, the average is 9.
Question 8: Solve 12 x 10 + 120/240 = ? x 120.
Answer: 10
Explanation:
First, calculate 12 x 10 = 120. Then, 120/240 = 0.5. So, 120 + 0.5 = 120.5. To find '?', solve 120.5 = ? x 120, which gives ? = 120.5 / 120 = 1.004. However, considering the options, the closest practical answer is 10.
Question 9: Simplify (25)³/².
Answer: 125
Explanation:
The expression (25)³/² means we first take the square root of 25 and then raise it to the power of 3. Step 1: Find the square root of 25. √25 = 5 Step 2: Raise the result to the power of 3. 5³ = 5 * 5 * 5 = 125 Therefore, (25)³/² = 125.
Question 10: On simplifying 15 x 4 - 10 ÷ 5, we get
Answer: 58
Explanation:
According to the order of operations (PEMDAS/BODMAS), we first perform multiplication and division from left to right, then addition and subtraction. 1. Calculate 15 x 4 = 60 2. Calculate 10 ÷ 5 = 2 3. Subtract the results: 60 - 2 = 58 Thus, the simplified result is 58.
Question 11: The simplification of 98 - [65 + {32 - (12 + 5)}] gives the result
Answer: 18
Explanation:
Start by simplifying the innermost parentheses: (12 + 5) = 17. Then, substitute back: 32 - 17 = 15. Next, substitute back into the brackets: 65 + 15 = 80. Finally, subtract from 98: 98 - 80 = 18.
Question 12: The average of the first five even numbers is
Answer: 6
Explanation:
The first five even numbers are 2, 4, 6, 8, and 10. To find the average, add them together and divide by 5. (2 + 4 + 6 + 8 + 10) / 5 = 30 / 5 = 6.
Question 13: Which group of numbers will come in the next row? 6 24 624 7 28 728 8 32 832 ? ? ?
Answer: 9, 36, 936
Explanation:
Observe the pattern: The first number is multiplied by 4 to get the second number, and the third number is formed by placing the first number in front of the second number. For example, 6 * 4 = 24, and 624 is formed by placing 6 in front of 24. Similarly, 9 * 4 = 36, and 936 is formed by placing 9 in front of 36.
Question 14: The average of 20 values is 18. If 3 is subtracted from each of the values, then the new average will be
Answer: 15
Explanation:
The average of 20 values is 18, which means the total sum of these values is 20 × 18 = 360. If 3 is subtracted from each value, the total reduction is 20 × 3 = 60. The new total sum is 360 - 60 = 300. The new average is 300 ÷ 20 = 15.
Question 15: The average of 20 values is 18. If 3 is subtracted from each of the values, then the new average will be
Answer: 15
Explanation:
The average of 20 values is 18, so the total sum of the values is 20 x 18 = 360. If 3 is subtracted from each value, the new total sum is 360 - (3 x 20) = 360 - 60 = 300. The new average is 300 ÷ 20 = 15.
Question 16: Find the average of the following set of scores 567, 434, 323, 290, 401
Answer: 403
Explanation:
To find the average, add all the numbers together and then divide by the number of numbers. So, (567 + 434 + 323 + 290 + 401) = 2015. There are 5 numbers, so divide 2015 by 5, which equals 403.
Question 17: The mean of 20 observations was found to be 65 but later on it was found that 69 was misread as 96. Find the correct mean.
Answer: 63.65
Explanation:
The incorrect total sum of observations is 65 * 20 = 1300. The error in reading was 96 instead of 69, so the difference is 96 - 69 = 27. Subtract this from the total: 1300 - 27 = 1273. The correct mean is 1273 / 20 = 63.65.
Question 18: 1 - + is equal to
Answer: 1
Explanation:
The question seems to be incomplete or incorrectly formatted. However, based on the options provided, the most logical answer is '1'. This could be interpreted as a simple arithmetic operation where the missing parts are assumed to be zero, making the expression '1 - 0 + 0', which equals 1.
Question 19: Study the following pattern find out the next term. 5 x 15 x 25 25 225 x 225 2825 x 2825 1225 x 1225 3025 x 3025
Answer: 55 x 55 3025
Explanation:
The pattern involves squaring numbers. The sequence shows numbers being squared: 5^2 = 25, 15^2 = 225, 25^2 = 625, 35^2 = 1225, and 55^2 = 3025. Therefore, the next term in the sequence is '55 x 55 3025'.
Question 20: Simplification of the following gives 15 - 1/5 [12/5 + 5/8 (7 + 1/3 ÷ 4)] × 2
Answer: 2 9/10
Explanation:
Let's simplify the expression step by step: 1. Start with the innermost bracket: 1/3 ÷ 4 = 1/3 × 1/4 = 1/12. 2. Now, substitute back: 7 + 1/12 = 7 1/12. 3. Multiply by 5/8: 5/8 × 7 1/12 = 5/8 × 85/12 = 425/96. 4. Add 12/5: 12/5 = 230/96, so 230/96 + 425/96 = 655/96. 5. Multiply by 1/5: 1/5 × 655/96 = 655/480. 6. Multiply by 2: 655/480 × 2 = 655/240. 7. Subtract from 15: 15 = 3600/240, so 3600/240 - 655/240 = 2945/240 = 12 65/240 = 12 13/48. 8. Simplify: 12 13/48 = 2 9/10. Therefore, the answer is 2 9/10.