Answer:
The easiest approach is to realise that one hour is 3 times longer than 20 minutes. The longer the time, the more they will pave.
215 of a mile, in 20 minutes, how much in 60 minutes?#
They will pave 3 times more.
215×31=615 of a mile
615=25 of a mile
You could also use the 'unitary method' where you find out how much they pave in ONE minute (divide by 20) and them multiply by 60 to find how much in one hour.
Look at what happens:
215÷20×60
=215×120×603
=215×3 ← exactly the same maths.
=25
Answer:
P4200
Step-by-step explanation:
SI=PRT/100
P=Principal which is P10500
R=Rate which is 20%
T=Time which is 2 years
So SI= 10500×20×2/100
=P4200
If nCk represents the number of ways k parts can be chosen from a pool of n, the probability of interest is the complement of the probability of selecting all good parts.
1 - (167C3)/(170C3) = 42,085/804,440 ≈ 0.0523
_____
nCk = n!/(k!(n-k)!)