The number of Roberto's baseball cards is 3/4 the number of David's cards. If Roberto gives 1/2 of his cards to David, What will be the ratio of Roberto's cards to David's cards?

2 answers

The ratio of Roberto's cards to Davids cards is 3:4. After giving half his cards, the ratio becomes 3 - 3/2 to 4 + 3/2, or 3/2 to 11/2, so the ratio now becomes 3:11. ☺☺☺☺
r/d = 3/4
(r/2)/(d+r/2)
= r/(2d+r)
= 1/((2d+r)/r)
= 1/(2d/r + 1)
= 1/(2(4/3)+1)
= 1/(11/3)
= 3/11