How many combinations exist for the letters m, n, o, p, and q taken 3 at a time?

 The required number of combinations is 10.

Step-by-step explanation:  We are given to find the number of combinations that exists for the letters m, n, o, p, and q taken 3 at a time.

We know that

the formula for the combination of s objects taken r at a time is given by

For the given combination, we have 5 letters and we are to take 3 at a time.

So, s = 5   and   r = 3.

Therefore, the required number of combinations is

Thus, the required number of combinations is 10.

the ratio of grapes to blueberries she should use is 12: 3

step-by-step explanation:

if mandie is making 15 cups of fruit salad, the ratio of grapes to blueberries she should use is 12: 3.