Question

The sum of 15% of a positive number and 10% of the same number is 70. What is twice of the number ?
A. 440
B. 280
C. 560
D. 140

Answer 1

Correct Answer - C
(c ) Let the positive no. be x
According to question 15% of x +10% of x =70
`implies x xx (15)/(100)+(x xx10)/(100)=70`
`implies (15x)/(100)+(10x)/(100)=70`
`implies(25x)/(100)=70`
`:. X=(70 xx100)/(25)=280`
`:.` Double of given no. `=280xx2=560`
Alternate Solution :
According ot question
25%=70
`:. 100%=280`
`:. 200%=560`