Answer:
4 because I know it's right
Answer:
15 and 5 hours.
Step-by-step explanation:
Call x the time taken by the first chap, and y the second.

Let's divide by 5 and play with the LHS of the first equation a bit:
we know how much x+y is ( first equation!) let's solve.
At this point it's easy to check that 
Answer:
680700
Step-by-step explanation:
this method can calculate more quickly
I'm not sure on this one but try .30 and .90 but don't count on it to much
Answer:
$50 - $9.99 = $40.01
$40.01 ÷ $3.99 = 10
so the answer is 10
Step-by-step explanation:
if thats not whats being asked sorry