25% of 80
25/100 or 1/4 x 80 = 20
So $20 were spent on shorts, then $60 were left over.
65% of 60 on sandals.
so 65/100 x 60 = 39
So we can see that the sandals cost $39.
Wa=0.5Wb, Ha=20, Hb is unkown
the area of rectangle a is : Wa*20
the area of rectangle b is : Wb*Hb
Rectangle a has 7 times the area of rectangle b: Wa*20=7*Wb*Hb
Replace Wa with 0.5Wb: 0.5Wb*20=7Wb*Hb => Hb=10/7
