If 5 key chains cost 11.25 then 15 key chains cost?

Answer 1

If 5 key chains cost 11.5 then one key chain costs 11.5 divided by 5, which is 2.3 so 15 key chains cost 2.3 x 15, which is 34.5

Actually the cost of 5 chains is 11.25 not 11.50.

so divide 11.25 by 5 to find the cost of one chain = 2.25

now multiply 2.25 by 15 to find the cost of 15 chains = 33.75

Another way to do it is to see that 15 chains is 3 times more than 5 so multiply the cost of 5 chains by 3

5x3 = 33.75