Answer: d. 6
Explanation: you multiply each number by 6 every time
rob can dig 1/10ft in one hour
Shayna can dig 1/7ft in one our
together they can dig
1/10+1/7
(7+10)/70 in one hour
17/70
in for hours they can dig
17/70×4
68/70
the left work is 2/70
in 60 minutes they can dig 17/70
1/70 work can be done in 60 minutes/17
2/70 work can be done in 60/17×2 minutes
7.088 minutes
for the entire work they take 4hours and 7 minutes

So, the answer to this problem is
x = 9/2 or
x = 4.5.
The answer is C, 4.
you combine like terms and that is the answer you get.
1. 70 dimes and 33 quarters
2. 18 dimes and 9 nickels
3. 236 adults and 342 children
4. 12 quarters, 9 dimes
5. 9 nickels, 18 dimes