How many three-letter (unordered) sets are possible that use the letters q, u, a, k, e, s at most once each? (No Response) 20 sets

20sets

Step-by-step explanation:

Since we are to select 3 unordered letters from the word q, u, a, k, e, s, we will apply the combination rule.

For example if r objects are to be selected from n pool of objects, this can be done in nCr number of ways.

nCr = n!/(n-r)!r!

Since the total number of letter in the word q, u, a, k, e, s is 6letters and we are to form 3 letters from it unordered, this can be done in 6C3 number of ways.

6C3 = 6!/(6-3)!3!

6C3 = 6!/3!3!

6C3 = 6×5×4×3×2×1/3×2×1×3×2×1

6C3 = 6×5×4/3×2

6C3 = 120/6

6C3 = 20

Hence 20sets of selection are possible

step-by-step explanation:

the ratio of red paint to blue paint is always 9/7. that means that, whatever x's value, (4x+12)/(4x-4) has that same ratio. so, set up an equation and cross-multiply to solve for x:

9/7 = (4x+12)/(4x-4)

9(4x-4) = 7(4x+12)

36x - 36 = 28x + 84

8x - 36 = 84

8x = 120

x = 15