Percentage, General Mathematics

Question: For a sphere of a radius `10` cm, the numerical value of surface area is what percent of the numerical value of its volume ?
A
`24%`

B
`26.5%`

C
`30%`

D
`45%`

Note: surface area `= 4 πR^2` `= 3/R (4/3 π R^3)` `= 3/4 xx Volume When `R = 10.` we have `S = 3/10 V` `= (3/10 xx 100)% of V` `= 30% of V.`
1. Report
Question: The radius of a sphere is increased by `50%`. The increase in surface area of the sphere is :
A
`100%`

B
`125%`

C
`150%`

D
`200%`

Note: Let original radius`= R, New radius `= 150/100 R` `= 3/2 R.` Original Surface area `= 4 π R^2` New surface area `= 4 π (3/2 R)^2` `= 9 π R^2` :. Increase`= ((5 π R^2)/(4 π R^2) xx 100)%` `= 125%.`
1. Report
Question: A cricket team won `40%` of the total number of matches it played during a year. If it lost `50%` of the matches played and `20` matches were drawn , the total number of matches played by the team during the year was :
A
`200`

B
`100`

C
`50`

D
`40`

Note: `40% of x + 50% of x + 20 = x` `=> 40/100 x + 50/100 x + 20 = x` `or x = 200.`
1. Report
Question: Arun gave a portion of the money he had to Gopal. Gopal in turn gave `40%` of what he got from Arun to Dinesh. How much money did Dinesh get ? To find out the answer, which of the following informations given in statements (p) and (Q) is∕are sufficient ? P: Arun had Rs.`4,000` with him. Q: The difference between the amounts of Gopal and Dinesh was `Rs. 500`
A
Only Q is sufficient

B
Only P is sufficient

C
Either P or Q is sufficient

D
Both P and Q together are needed

Note: P:A`= 4000 & Q : G - D = 500` Clearly, `D = 40% of G or G = 100/40 D` `= 5/2 D.` `:. D - G = 500 => 5/2 D - D` `= 500 or D = 1000/3` Thus, only Q is sufficient
1. Report

First Prev 10 11 12 Next Last

Question: For a sphere of a radius `10` cm, the numerical value of surface area is what percent of the numerical value of its volume ?

Question: The radius of a sphere is increased by `50%`. The increase in surface area of the sphere is :

Question: A cricket team won `40%` of the total number of matches it played during a year. If it lost `50%` of the matches played and `20` matches were drawn , the total number of matches played by the team during the year was :