Three medium pizzas cost $10.50. How much does it cost to buy 10 medium pizzas

Question

if 3 medium pizzas cost $10.50 how much do 10 pizzas cost?

Answer 1

10.50/3 = 3.50

so 10 costs $35

Alternatively, 3/10.50 = 10/x

105 = 3x

x=35