Perry finished a 100-meter race in 7/8 of a minute. The winner of the race used 14/15 of Perry's time to finish the race. How much time did the winner use to finish the race?

49 seconds

Step-by-step explanation:

The time perry used is 7/8 of a minute

a minute equals to 60 seconds

so the time perry used is 7/8 x 60 = 52.5 seconds

The winner used 14/15 of 52.5 seconds (perrys time)

so 14/15 x 52.5 = 49 seconds

hello from mrbilldoesmath!

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

discussion:

in general, the factorization of a^3 + b^3 is

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

in our case note that 343 = 7^3 and 216 = 6^3 so the equation becomes:

343x^3 + 216y^3 = (7x)^3 + (6y)^3

if you think of a (above) as 7x and b as 6y the factorization becomes

343x^3 + 216y^3 =

((7x + 6y) (   (7x)^2 - 7x*6y + (6y)^2)   =

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

you,

mrb

(a + b) (a^2 - a b + b^2)