(1) 34.8 liters
(2) $63.55
Solution:
(1) There is a mistake in question. It is 42 liters.
Total gasoline a car can hold = 42 liters
Liters of gasoline filled in beginning of the week = 35.8
Liters of gasoline used during the week = 28.6
Remaining liters of gasoline in the tank = 35.8 – 28.6
= 7.2 liters
Quantity of gasoline need to buy to fill the tank completely
= Total capacity – Remaining gas in the tank
= 42 liters – 7.2 liters
= 34.8 liters
Hence Alberto need to buy 34.8 liters of gasoline to fill the tank.
Option B is the correct answer.
(2)
Shamika earns in first week = $25.75
Shamika earns in next week = $37.80
Total money Shamika have = First week earning + Second week earning
= $25.75 + $37.80
= $63.55
Don't add or subtract spending money, because the question is how much she have from these two weeks.
Hence Shamika have $63.55 from these two weeks.
![\bf \textit{exponential form of a logarithm} \\\\ \log_a(b)=y \qquad \implies \qquad a^y= b \\\\[-0.35em] ~\dotfill\\\\ \log(x) = 6.4\implies \log_{10}(x)=6.4\implies 10^{6.4}=x\implies 2511886.43\approx x](https://tex.z-dn.net/?f=%5Cbf%20%5Ctextit%7Bexponential%20form%20of%20a%20logarithm%7D%20%5C%5C%5C%5C%20%5Clog_a%28b%29%3Dy%20%5Cqquad%20%5Cimplies%20%5Cqquad%20a%5Ey%3D%20b%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20%5Clog%28x%29%20%3D%206.4%5Cimplies%20%5Clog_%7B10%7D%28x%29%3D6.4%5Cimplies%2010%5E%7B6.4%7D%3Dx%5Cimplies%202511886.43%5Capprox%20x)
let's recall that when the base is omitted, "10" is implied.
2 / 4 x 100
= .50 x 100
= 50%
