There are 8 marbles in a bag, each with a different color. How many different groups of 4 marbles can we select?

70

Step-by-step explanation:

8 choose 4

= (8!)/(4!*4!)

=(8*7*6*5)/(4*3*2*1)

=1680/24

=70

b. x- 48 =120

step-by-step explanation:

$25

step-by-step explanation:

25 - 4.50 = 20.5

20.5 / 2 = 10.25

10.25 + 10 = 20.25

20.25 - 12.50 = 7.75

therefore the answer is $25 as shown as the first number.