Answer:
Step-by-step explanation:
x is the score she got on the fifth test.
Since her average score is 88, the sum of all five tests is 5×88.
x + 87 + 75 + 93 + 85 = 5×88 = 440
x = 440 - 87 - 75 - 93 - 85
x = 100
She got a 100 on her fifth test.
1/6 If you have a graphing calculator, it would be simple to type in the fraction as a division equation then type MATH, ENTER, ENTER.
Answer:
the question is incomplete, so I looked for a similar one:
<em>After the release of radioactive material into the atmosphere from a nuclear power plant, the hay was contaminated by iodine 131 ( half-life, 8 days). If it is all right to feed the hay to cows when 10% of the iodine 131 remains, how long did the farmers need to wait to use this hay? </em>
iodine's half life (we are given x, we need to find b):
0.5A₀ = A₀eᵇˣ
x = 8 days
we eliminate A₀ from both sides
0.5 = eᵇ⁸
ln 0.5 = ln eᵇ⁸
-0.69315 = b8
b = -0.69315 / 8 = -0.08664
since the farmers need to wait until only 10% of the iodine remains (we already calculated b, now we need to find x):
0.1A₀ = A₀eᵇˣ
0.1 = eᵇˣ
ln 0.1 = bx
where b = -0.08664
x = ln 0.1 / -0.08664 = -2.302585 / -0.08664 = 26.58 days
Answer:
2 : 14
Step-by-step explanation:
