An observational study showed that the average four-year-old could assemble a toy in 15 seconds. the average five-year-old could assemble the same toy 40 percent faster. how many seconds did it take the average five-year-old to assemble the toy?

you find 40 percent of fifteen, and subtract it. so the correct answer is 9 seconds

He could assemble it in 9 seconds.

Step-by-step explanation:

40 percent of 15 is 6. 15 - 6 is 9. You would subtract six because the five year old did it faster but if he did it 40 percent slower it would have taken him 21 seconds. Hope this helps:)

hello from mrbilldoesmath!

answer:

x - 3

discussion:

x^2 - 9 = (x-3) (x+3)   so

(x^2-9)/ (x + 3) = x-3

you,

mrb

option (b) is correct

step-by-step explanation:

to find the solution of this system, we need to convert it into reduced row-echelon form. we have,

after applying row operations r2 -> r2/2 and r3 -> r3/3, we get,