One pipe can fill a tank with oil in 3 hours. A second smaller pipe can fill the same tank in 7 hours. If both pipes were used at the same time, how long would they take to fill the tank?

2.1 hours.

Step-by-step explanation:

Given , Time taken by the first pipe to fill  a tank = 3 hours

Time taken by the second pipe to fill the tank = 7 hours

If both pipes were used at the same time,  then the time taken (t) by both of them to fill the tank ( together) will be :-

Therefore, time taken to fill the tank = 2.1 hours.

all the angles opposite to the angle 150 would be 150 and all the angles that are next to 150 are 30 because they equal 180 it you add it up.

step-by-step explanation: