12. 37, 370, 10^2
13. 20.4, 10^2, 2040
15. 1000*1.75=1750
Hope it helped!
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:
answer is D
Step-by-step explanation:
APEX :)
Answer:
b= -3
Step-by-step explanation:
can i have brainliest?