Answer:his speed in still air is 6 miles per minute.
the speed of the wind is 1 mile per minute.
Step-by-step explanation:
Let x represent his speed in still air.
Let y represent the speed of the wind.
It takes Jack Frost 5 minutes to fly 35 miles with the wind. This means that his total speed would be x + y
Distance = speed × time
It means that
35 = 5(x + y)
35 = 5x + 5y - - - - - - - - - - -1
It takes him 7 minutes to go 35 miles against the wind. This means that his total speed would be x - y
It means that
35 = 7(x - y)
35 = 7x - 7y - - - - - - - - - - -2
Multiplying equation 1 by 7 and equation 2 by 5, it becomes
245 = 35x + 35y
175 = 35x - 35y
Adding both equations, it becomes
420 = 70x
x = 420/70 = 6
Substituting x = 6 into equation 1, it becomes
35 = 5 × 6 + 5y
35 = 30 + 5y
5y = 35 - 30 = 5
y = 5/5 = 1
Answer:
B) 7.5 in3
Step-by-step explanation:
Answer:
19
Step-by-step explanation:
Plug in
now, there are 12 months in a year, so 18 months is really 18/12 of a year, thus
![~~~~~~ \textit{Simple Interest Earned Amount} \\\\ A=P(1+rt)\qquad \begin{cases} A=\textit{accumulated amount}\dotfill & \$4000\\ P=\textit{original amount deposited}\\ r=rate\to 5\%\to \frac{5}{100}\dotfill &0.05\\ t=years\to \frac{18}{12}\dotfill &\frac{3}{2} \end{cases} \\\\\\ 4000=P[1+(0.05)(\frac{3}{2})]\implies 4000=P(1.075) \\\\\\ \cfrac{4000}{1.075}=P\implies 3720.93\approx P](https://tex.z-dn.net/?f=~~~~~~%20%5Ctextit%7BSimple%20Interest%20Earned%20Amount%7D%20%5C%5C%5C%5C%20A%3DP%281%2Brt%29%5Cqquad%20%5Cbegin%7Bcases%7D%20A%3D%5Ctextit%7Baccumulated%20amount%7D%5Cdotfill%20%26%20%5C%244000%5C%5C%20P%3D%5Ctextit%7Boriginal%20amount%20deposited%7D%5C%5C%20r%3Drate%5Cto%205%5C%25%5Cto%20%5Cfrac%7B5%7D%7B100%7D%5Cdotfill%20%260.05%5C%5C%20t%3Dyears%5Cto%20%5Cfrac%7B18%7D%7B12%7D%5Cdotfill%20%26%5Cfrac%7B3%7D%7B2%7D%20%5Cend%7Bcases%7D%20%5C%5C%5C%5C%5C%5C%204000%3DP%5B1%2B%280.05%29%28%5Cfrac%7B3%7D%7B2%7D%29%5D%5Cimplies%204000%3DP%281.075%29%20%5C%5C%5C%5C%5C%5C%20%5Ccfrac%7B4000%7D%7B1.075%7D%3DP%5Cimplies%203720.93%5Capprox%20P)
Answer:
23.92
Step-by-step explanation:
You can round 2.99 to 3 and do 3x8 mentally then subtract 8 cents ¯\_(ツ)_/¯
