A jar contains 10 red marbles and 30 green marbles. how many red marbles must be added to the jar so 60% of the marbles will be red

2
red balls = 10
green balls = 30

let the total number of balls be x.

therefore according to problem ,

30 = ( 100 - 6 0 ) % x
= 40 % x.

therefore ,

45 = 60 % x .


therefore number of total number of red balls = 45.

and the number of red balls added = 45 - 10
= 35 .

Answers

2014-05-08T22:12:47+05:30
Let number of marbles to be added = x
Then,
(10 + x) = 60% of (30 + 10 + x)
10 + x = 60/100*40 + 60/100 * x
x - 6x/10 = 24 - 10
4x/10 = 14
x = 14*10/4
x = 35
So, 35 marbles should be added.
2 5 2
2014-05-08T23:21:16+05:30
 35 marbles must be added to the jar so 60% of the jar is red.
1 5 1