Calculate.
gC4
Note: nCr =
n!
r!(n-r)!

Acar started driving from city a to city b, distance between which is 620 miles, at a rate of 60 mph. two hours later a truck left city b and started moving towards city a at a rate of 40 mph. how many hours after the truck's departure will the two meet?

2. explain in words how you plot the point (4, −2) in a rectangular coordinate system.

Which radical expression is a rational number? a. √ 360 b. √ 644 c. √ 225 d. √ 122