Brian can lay a slab of concrete in 6 hours, while Greg can do it in 4 hours. If Brian and Greg work together, how long will it take?

2 2/5 hours

Step-by-step explanation:

In 6 hours Brian can lay 1 slab of concrete

dividing both side by 6

in 6/6 hours Brian can lay 1/6 slab of concrete

Thus, in 1 hour  Brian can lay 1/6 slab of concrete

In 4 hours Greg can lay 1 slab of concrete

dividing both side by 4

in 4/4 hours Greg can lay 1/4 slab of concrete

Thus, in 1 hour  Greg can lay 1/4 slab of concrete

Thus, total part of slab laid by both in 1 hour when they work together

1/6 + 1/4 = 4+6/(6*4) = 10/24 = 5/12

5/12 of slab of concrete is laid by both of them in 1 hour

time taken to lay 5/12 of slab = 1 hour

dividing both side by 5/12

time taken to  5/12/ 5/12 of slab = 1/5/12 hour = 12/5 hours

time taken to 1/1 of slab = 12/5 hours = 2 2/5 hours

Thus,

it takes 2 2/5 hours to lay the full slab of concrete when Brian and Greg work together,

its 69.420

step-by-step explanation:

answer: the value should be used for i in the formula of calculation the monthly payment , the interest rate per period is 0.85.

step-by-step explanation:

the given rate of interest i= 85%

in calculating the monthly payment for a loan with an interest rate compounded monthly, the value of the interest rate per period we use in the formula must be in decimal form.

to convert it in decimal, we divide it by 100, we get

hence, the value should be used for i in the formula of calculation the monthly payment , the interest rate per period is 0.85.