One fifth of a number is subtracted from four fifth of the same number. If the result is 9, what is the number.
1 answer:
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Answer:
look at explanation
Step-by-step explanation:
To solve all of these questions you just need to scale. While scaling you can divide or multiply.
1. (divide by 4 to get unit rate)
unit rate =
2. If it takes one hour to travel 40 miles, then we don't have to scale or anything. We know , the answer is...
"It'll only take one hour to travel 40 miles. This is correct because the unit rate is . "
3. Knowing that the constant speed of the plane is , we can scale then add half of the unit rate to get our answer.
x 3 =
800 x 3 = 2400
then add half of unit rate which is
= 400
so, our answer is
4. <--- ( divided by 2)
( multiplied x 2.5) --->
To get an easier way to find the answer, if possible you can scale back farther than the 1 hour mark.
Elmer would take 2 and a half hours to ride 15 km.
5. The boys speed is . All we need to do is divide by 2.
= 4