Math(Please help)
posted by Hannah on .
1) h(t)=20(5/8)  16(5/8)^2 + 10 = 65/4
All I need to know for this is how to calculate the fraction parts to get 65/4. I am not good with fractions.
2) A manufacturer's profit from producing x units of a product is given by P(x)=0.002x^3  0.01x^2 + 0.5x. At what production level(s) will the marginal profit be $9.30 per unit. Enter just an integer, no units.
the derivative would be p(x)=0.006x^2  0.02x + 0.50. Then would I just plug in 9.30 to x?

1) (5/8)^2 = (5/8)(5/8) = 25/64
h(t) = 100/8  16 (25/64) + 10 =
800/64  400/64 + 640/64 = 1040/64 = 65/4
2) I would just plug the value in, but I don't know which equation you want to use. 
so 0.006(9.30)^2  0.02(9.30) + 0.50

For the first question how did you get 800/64 and 640/64?

The 20*(5/8)^2= 20*25/64
The 640/64 came from 10= 10*64/64