Let x be the number of pounds. Difference between selling and buying
price is 10$

x/4 - (x/3)*.5 = 10

Solving for x, we get 120

dunkin77 wrote:Hi,

somehow I got the answer (D) but I guess there is an easier way to do it....

A grocer purchased a quantity of bananas at 3 pounds for $0.50 and sold the entire quantity at 4 pounds for $1.00. How many pounds did the grocer purchase if the profit from selling the bananas was $10.00?
(A) 40
(B) 60
(C) 90
(D) 120
(E) 240

There is a way but I dont know whether it is easier

Here buying price is given for 3 pounds
and Selling price is given for 4 pounds

let us calculate the profit for 12 pounds ( 12 is the LCM of 3 and 4)

Cost for buying 12 pounds = $2
Revenue after selling 12 pounds = $3

Profit after selling 12 pounds =$1

now, it's easy!!! He has to sell 12*10 pounds for $10 profit

it is 120 pounds

Ohh okay - thanks both for your help! both looks easier than my way!

Let us assume he purchased x pounds

Cost of 1 pound = .5/3. Therefore cost of x pounds = .5x/3

S.P of 1 pound = 1x/4 - .5x /3 = 10

Therefore x = 120