Number 19
price :$16
pay :10%
ask:each monthly payment
answer:
pay =10%×$160=$16
each monthly payment
={$160-$16}÷6
144÷6
$24
number 20
weight earth:150 pounds
ratio :5:7
weight neptune :7/5×150=210 pounds
Let's look at work rates per minute.
Together they can paint the wall in x minutes.
Working together, in 1 minute, they do 1/x of the job.
The student who paints the wall in 16 minutes does 1/16 of the job in 1 minute.
The student who paints the wall in 24 minutes does 1/24 of the job in 1 minute.
Together, they do 1/16 + 1/24 of the job in 1 minute, but from above, we see that together, they do 1/x of the job in 1 minute, so 1/16 + 1/24 must equal 1/x. That gives us our equation.
1/16 + 1/24 = 1/x
1/16 * 3/3 + 1/24 * 2/2 = 1/x
3/48 + 2/48 = 1/x
5/48 = 1/x
x = 48/5 = 9.6
Answer: It takes them 9.6 minutes, or about 10 minutes to do the job together.
Answer:
<h2>
67.7</h2><h2 />
Step-by-step explanation:
perimeter = semicircle (x2) + parallelogram side (x2)
= 1/2 π 12 (x2) + 15 (x2)
= 37.7 + 30
= 67.7
