Answer:
I dont know what to say
Step-by-step explanation:
A=g≈-32
v=⌠a dt since a≈-32
v=-32t+C, where C is the initial velocity, which we are told is 20 ft/s
v=-32t+20
h=⌠v dt
h=-32t^2/2+20t+C, where C is the initial height, so what is a reasonable initial height? How about 3 ft since we are swinging a bat around maybe our waist level... maybe :P
h=-16t^2+20t+3
Your choices may have made a different assumption about the initial height of course but you did not show your choices, but certainly it will be:
h(t)=-16t^2+20t+hi, where hi is the initial height in feet.
This of course ignores air resistance and flight dynamics of a spinning ball with seams, which will make a significant difference in real life :)
If she is making 6 costumes that need 3 7/9 yards each, the equation would be 6 x 3 7/9.
The answer to that equation would be 22 2/3.
How to get the answer:
3 x 6 = 18
7 x 6 = 42 (the seven is from the 7/9)
42/9 = 4 2/3
then add the eight teen and the 4 2/3 and you get 22 2/3.
Let: x be Amy's marbles
3x be Robin's marbles
15+3x be Sam's marbles
x+3x+15+3x=99
7x+15=99
7x=99-15 (transfer 15 to the right side of the equation, then minus)
7x/7=84/7 (divide both sides of the equation by 7)
x=12
Now substitute:
x = 12 (Amy's)
3x = 3*12 = 36 (Robin's)
15+3x = 15+3*12 = 51 (Sam's)
12+36+51 = 99
Therefore, Amy has 12 marbles, Robin has 36 marbles and Sam has 51 marbles.