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ACT Mathematics Videos 164 videos
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ACT Math 4.4 Pre-Algebra 509 Views
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Description:
ACT Math: Pre-Algebra Drill 4, Problem 4. Using the information given, find out how many girls attend the school.
Transcript
- 00:03
Here's your shmoop du jour:
- 00:04
The ratio of boys to girls at the local middleschool is 3 to 4.
- 00:08
If there are 245 students at the school, how
- 00:11
many girls are there?
- 00:13
And here are the potential answers...
Full Transcript
- 00:19
So obviously this is a GREAT school to attend if you're a boy who likes going out Saturday nights.
- 00:24
It's a simple ratio problem. The problem tells us that the boys to girls ratio is:
- 00:31
3x boys and 4x girls. Meaning... there are more girls than boys...
- 00:38
It also gives the TOTAL number of students, which is 245.
- 00:41
There's a simple ratio here. 4 out of 7 students are girls.
- 00:45
So the ratio is "4 is to 7 as x is to 245."
- 00:53
To get the answer, we cross multiply to get 7x equals 4 times 245...
- 00:58
...or 7x equals 980.
- 01:02
To solve for x... which is the number of boys in the school... we divide both sides by 7
- 01:07
to get x = 140.
- 01:09
The answer is E.
- 01:10
As in, "Edwina."
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