Joey puts 25% of his allowance into savings each week. if last week he put 10$ in savings, what was his allowance last week?

$40

Step-by-step explanation:

25% is 1/4.

If 10 is 1/4 of the full amount, then you take 10 and multiply by 4 to get the full amount.

10 times 4 equals 40.

hello from mrbilldoesmath!

answer:

(7 x + 6 y) (49 x^2 - 42 x y + 36 y^2)

discussion:

the trick is to recognize that 343 = 7^3 and 216 = 6^3 and, in general,

a^3 + b^3 =   (a + b) (a^2 - a b + b^2).

in our case

343x^3+216y^3   =   (7x)^3 + (6y)^3

so take a = 7x and b = 6y in the above equation to get the answer.

you,

mrb