The equation for:

Judy and Linda agree to share the cost
of a $21 pizza based on how much each one ate. If Judy ate 3/4 of the amount that Linda ate, how much should each pay?
what is the formula please.

1 answer

if Linda paid x, then Judy should pay 3/4 x

Add it all together to get the whole cost:

x + 3/4 x = 21
7/4 x = 21
x = 21 * 4/7 = 12

So, Linda paid $12, Judy paid $9