At th zoo, there were 3 times as many monkeys as lions. Tom counted a total of 24 monkeys and lions. How many monkeys were there?

If there were m monkeys, then the rest (24-m) were lions.

m = 3(24-m)
...

To find the number of monkeys at the zoo, we need to set up an equation based on the information given. Let's assume the number of monkeys is 'm' and the number of lions is 'l'.

From the given information, we know that the number of monkeys is 3 times the number of lions, so we can write the equation as:
m = 3l

We also know that the total count of monkeys and lions is 24, so we can write another equation as:
m + l = 24

Now we have a system of two equations with two variables. We can solve this system to find the values of 'm' and 'l'.

Substitute the value of 'm' in terms of 'l' from the first equation into the second equation:
3l + l = 24
4l = 24
l = 6

Now substitute the value of 'l' back into the first equation to find 'm':
m = 3l
m = 3(6)
m = 18

Therefore, there were 18 monkeys at the zoo.