An oil tanker can be emptied by the main pump in 4 hours. An auxiliary pump can empty the tanker in 11 hours. If the main pump is started at 7 PM, when should the auxiliary pump be started so that the tanker is emptied by 10 PM?

The pump should be added by 8PM

Step-by-step explanation:

An oil tanker can be emptied by the main pump in 4 hours.

An auxiliary pump can empty the tanker in 11 hours.

the main pump is started at 7 PM,and we have 10 PM - 7PM = 3 hours to empty the tank.

So we have to look for the combined rate of the both pumps .

Let's say the volume= x

Rate of first pump= x/4

Rate of second pump= x/11

The rate will be added together

Combined rate= x/11 + x/4

Combined rate= 15x/44

But they have three hours to complete their pump

15x/44 = 3

X=1.0227

The pump should be added by 8PM

answer

a,b, and d

explanation

a reflection angle is more than

but less than;

an angle that measures

is a reflex angle.(true)

an angle that measures less than

is acute.(true)

provided we are considering angles greater or equal to zero.

an acute angle lies in the range.

an obtuse angle is less than 180° but more than 90°

an angle that measures 300° is obtuse (false)

an angle that measures 65° is an acute angle.(true)

x is greater than 5

step-by-step explanation:

2x+7 is greater than 17

    -7                           -7

2x is greater than 10

divide by 2 each side

x is greater than 5