Answers

2014-04-23T12:15:11+05:30
You need to have 45 marbles in the jar to have 60% red.
You currently have 10 marbles.
N=45-10=35
You need to add 35 red marbles.
0
how do you know we need 45 marbles?
Ratio of Red total = R/R+30

where R is No. of red marbles

R/R+30 = 60/100
100R = 60(R+30)
100R= 60R+ 1800
40R = 1800
R = 45