Help on EASY math questions?

Test Preparation
1

<p>Just solve these in the simplest way, as you normally would. No need to be algebraic.</p>

<ol>
<li><p>In still water, a boy rows 5 miles an hour. With the aid of a current, he can make a 21 mile trip in 3 hours. How fast is the current?</p></li>
<li><p>It takes Bill 4 hours to do a job. It takes Joe 2 hours to do a job. How many jobs could they do together in 4 hours?</p></li>
<li><p>For the first 5 hours of a flight, a plane is assisted by a 100 mph wind. For the next 3 hours, it is hindered by a 100 mph wind. If total distance traveled is 3400, what's the plane's speed in windless condition?</p></li>
</ol>

<p>More to come</p>

2

<p>1)5 *3 = 15 (miles he could normally go in an hour) 21-15= 6 (more miles he went in 3 hours) 6/3= 2 (extra miles he went per hour) so the answer is 2 mph
2) 4/4 = 1 (job done by bill) 4/2 =2(jobs done by Joe) 2+1 = 3 jobs
3) 3400= 5(x+100) + 3(x-100) 3400= 5x+500 + 3x-300 3400= 8x +200 3200=8x x= 400 miles per hour. (sorry for the algebra that was the simplest way for me to do it.)</p>