Ratio:
Sparkling water / grape juice
1 1/2 / 3/4
a)
For 9/4 of grape juice:
x / 9/4
Equal both ratios:
1 1/2 / 3/4 = x /9/4
Solve for x:
(1 1/2 / 3/4) 9/4 = x
x= 4 1/2 of sparkling water
b)
For 15/4 of sparkling water:
15/4 / x
1 1/2 / 3/4 = 15/4 /x
x = 15/4 / (1 1/2 / 3/4)
x= 15/8
c)1 1/2 = 3/2