87 is a composite number because it is divisible by 3, all of the rest of the numbers are prime
a) 32.25* 40 = 1290
b) 32.25 (1.5) *12 =580.50
c) 1290+580.50=1870.50
Let

be the amount of time it takes to perform an arm routine and

be the amount of time it takes to perform an abdominal routine. We see:


Subtracting the second equation from the first gives

. Substituting gives

, so

and

.
Thus, an arm routine takes ten minutes and an abdominal routine takes thirty minutes.
Answer:
80 km/hr
Step-by-step explanation:
This is asking for speed.
Speed=Distance/Time
Speed=720/9
Speed=80 km/hr