Question

If 3 mangoes cost 40.00,how much would you pay for 1 1/4 dozens?

Answer 1

well, 1 1/4 dozen mangoes would be
15 mangoes.

so if 3 of them cost 40.00
then 15 would cost ..... ??

(sure hope that is not $40.00 for 3 mangoes)

Answer 2

I guess you could do cross multiply but the first sentence wasn't clear

Answer 3

just use common logic
since we multiplied 3 by 5 to get 15
we have to multiply 40 by 5 to get 200
So 15 of them would cost 200

or

40/3 = x/15
3x = 600
x = 200
So, there is your cross-multiplication

or, use the Unit way:

if 3 mangoes cost 40
then 1 mangoe costs 40/3
and 15 mangoes cost 15(40/3) = 200