Question

Algebra 2 homework help!

Answer 1

3 and 15/16 hours

Explanation:

To find the time it takes them to do the job together, we use the equation

1/A + 1/B = 1/C

where A is the time it takes the first person to do the job

B is the time it takes the second person to do the job

and C is the time it takes them to do the job together

1/7 + 1/9 = 1/C

Multiply by 63, which is the common denominator on the left

63 *( 1/7 + 1/9) = 1/C *63

9+7 = 63/C

16 = 63/C

Multiply by C

16C = 63/C *C

16C = 63

Divide by 16

16C/16 = 63/16

C = 63/16

C = 3 15/16

Together it will take them 3 and 15/16 hours