Aptitude Problems On NumberPage 2
9. | | The difference between a number and its three fifth is 50. What is the number? | | (a)115 | | (b)120 | | (c)125 | | (d)130 |
|
Answer is: CLet, the number be X. then,
⇒ X – (3/5)X = 50
⇒ 2/5 X = 50
⇒ X = 125
10. | | A number whose fifth part increased by 4 is equal to its fourth part diminished by 10, is? | | (a)200 | | (b)240 | | (c)250 | | (d)280 |
|
Answer is: DLet, the number be X. Then,
( 1/5 X + 4) = (1/4 X – 10)
⇒ X/20 = 14
⇒ X = 280
11. | | If the sum of one half and one fifth of a number exceeds one third of that number by 22/3 , the number is? | | (a)17 | | (b)18 | | (c)19 | | (d)20 |
|
Answer is: DLet, the number be X.
Then, (1/2 X + 1/5 X) - 1/3 X = 22/3
⇒ 11/30 X= 22/3
X = (22 x 30) ÷ (11 x 3) = 20.
12. | | If 5/2 is added to a number and the sum multiplied by 9/2 and 3 is added to the product and then dividing the sum by 6/5 , the quotient becomes 25. What is the number? | | (a)7/2 | | (b)9/2 | | (c)7/3 | | (d)11/2 |
|
Answer is: ALet the number be X. then,
[9/2 (X + 5/2) + 3] ÷ (6/5) = 25
⇒ 9/2 X + 45/4 + 3 = 25 x 6/5
⇒ 9/2 X = 30 - 57/4
⇒ X = (63/4 x 2/9) = 7/2
13. | | One fifth of a number is equal to (5/8) of another number. If 35 is added to the first number, it becomes four times of the second number. The second number is? | | (a)20 | | (b)30 | | (c)40 | | (d)50 |
|
Answer is: CLet, the numbers be X and Y. Then,
1/5 X = 5/8 Y ⇒ Y = 8/25 X
Now, X + 35 = 4Y
X + 35 = 32/25 X
7/25 X = 35
X =[(35 x 25) ÷ 7] = 125
Second number Y = 8/25 X = 40
14. | | The difference between two positive integers is 3.If the sum of their square is 369, then the sum of the numbers is? | | (a)25 | | (b)26 | | (c)27 | | (d)28 |
|
Answer is: CLet the numbers be X and (X +3).
X² + (X + 3)² = 369
X² + X² + 9 + 6X = 369
2X² + 6X – 360 = 0
(X + 15)(X - 12) = 0, So X = 12.
So, the numbers are 12 and 15.
∴ Required sum = (12 +15) = 27
15. | | If the sum of two numbers of is 22 and sum of their squares is 404, then the product of the numbers is? | | (a)30 | | (b)40 | | (c)50 | | (d)60 |
|
Answer is: BLet, the numbers be X and Y.
Then, (X + Y) = 22 and X² + Y² = 404
Now, 2XY = (X + Y)² - (X² + Y²)
⇒ (22)² - 404 = 484 – 404 = 80
⇒ 2XY = 80
⇒ XY = 40
16. | | In two digit number, the digit in the unit's place is four times the digit in ten's place and sum of the digits is equal to 10. What is the number? | | (a)25 | | (b)26 | | (c)27 | | (d)28 |
|
Answer is: DLet the ten's digits be X. Then, unit's digit = 2X.
∴ X + 4X = 10 ⇔5X = 10
⇒ X = 2
So, Ten's digit = 2, unit's digit = 8.
Hence, the required is 28.
Comments