In a certain zoo, 9 Liters of water can sustain 5 monkeys. What is the

We can solve this question using equivalent ratios

Would use the ratio: liters of water/number of monkeys sustained
We'll let x = number of monkeys 16 liters of water can sustain

So we can write: 9/5 = 16/x
Cross multiply to get: 9x = (5)(16)
Simplify to get: 9x = 80
Divide both sides by 9 to get x = 80/9 = 8.something

This tells us that 16 liters of water CANNOT sustain 9 monkeys
So the maximum number of monkeys that CAN be sustained by 16 liters of water is 8

Answer: B

Cheers,
Brent

RELATED VIDEO

_________________

9 Liters of water can sustain 5 monkeys
1………………………………………..5/9
16………………………………………..5*16/9 =80/9 = 8.88

Maximum number of monkeys = 8(B)

We can create the proportion:

9/5 = 16/n

9n = 80

n = 80/9 = 8 8/9

Thus, the maximum number of monkeys that can be sustained is 8.

Answer: B

_________________

We're multiplying our amount of water by 16/9, so we can multiply our number of monkeys by 16/9. So we can sustain 80/9 monkeys, which is just less than 9, and since the answer must be an integer, the answer is 8.
_________________

Hi BrentGMATPrepNow, since question ask for maximum and we get answer 8.8 so round up to 9 but it seems is not right here.
So how do we decide when is ok to round up and when is not? Thanks Brent
Thanks Brent

We have enough water to sustain 8.8 monkeys.
So, we don't have enough water to sustain 9 monkeys.
And we don't have enough water to sustain 10 monkeys. etc.

However, we DO have enough water to sustain 8 monkeys.
And we DO have enough water to sustain 7 monkeys.
And we DO have enough water to sustain 6 monkeys.
And we DO have enough water to sustain 5 monkeys.
etc

What's the maximum number of monkeys 16 liters of water can sustain?
Well, we have enough water for 1 to 8 monkeys.
The biggest number is 8.
_________________

Get it thanks BrentGMATPrepNow . So it really is depends on type of question then.