1.) You have 12 toppings. You choose one topping--that leaves you with 11 toppings. You choose another--that leaves 10. 12×11×10 = 1,320.
Multiply 1,320 topping choices by 6 cheeses to get 7,920 total combinations.
2.) (Though I'm less sure of these)
CDs: 6×5×4×3×2 = 720
Cassettes: 5×4 = 20
DVDs: 8×7×6×5 = 1680
If A is equal to 30, and A+B equals 42. That means B equals 12. So, if the value increased with the same rate of change, it would be 54. This is because 30 plus 12 is 42. 42 plus 12 would equal 54.
Ok. In order to do this set up 2/5 divided by 5/7. The way you divide with fractions is by multiplying them but flipping the second fraction into 7/5 <---this is known as the reciprocal. In other words do:
2/5 x 7/5 =
14/25
There you go.
The distribution is symmetric, I had the same exercise!!
Let x be white marbles, y be yellow marbles
x+y=54…(1)
x=3y - 6 …(2)
put (2) into (1)
(3y - 6) + y = 54
4y = 60
y=15
put y=15 into (1)
x + 15=54
x=39
so y=15 x=39