The answer to this question is C
Answer:D) 1 hr
Step-by-step explanation:
Given
Pump A and B can fill tank in 
Pump A and C can fill tank in 
Pump B and C can fill tank in 
Let A be the total hr taken A therefore rate of 
Let B be the total hr taken B therefore rate of 
Let C be the total hr taken C therefore rate of 
-----1
-----2
-----3
Adding 1,2 & 3



thus time taken by A,B and C combined is 1 hr
Answer:11
Step-by-step explanation:
Boys : girls=7:1
Sum of ratio=7+1=8
Let them number of girls be y
Then they number of boys=y+66
Total number of pupils=y+y+66
Total number of pupils=2y+66
Number of girls=(girls ratio)/(sum of ratio) x (total number of pupils)
y=1/8 x (2y+66)
Cross multiply
y x 8=2y + 66
8y=2y + 66
Collect like terms
8y-2y=66
6y=66
Divide both sides by 6
6y/6=66/6
y=11
The number of girls is 11
The goal is to solve for y. Start by subtracting 2x from both sides. This gives you 8y=-2x+16. Now just divide both sides by 8, which gives you y=-2/8x+16/8. Finally, simplify this to y=-1/4x+2.
I hope this helps you
Area=length.width
343=l.w
7.7.7=l.w
l=49
w=7
Perimeter=2 (49+7)
Perimeter=2.56
Perimeter=112