Question

Help please.. I want to say B, but that would mean they aren't girls or boys..

Of the 150 students at Smith Elementary School, 22% were absent from school on Tuesday. Of the students who were absent, 20 of them were male. Which claim cannot be made based on the given information?

A. There are 150 students at Smith Elementary School.

B. 13 females were absent on Tuesday.

C. 78% of the students were not absent on Tuesday.

D. 78 of the students who were not absent on Tuesday were male.

Answer 1

In choice D you mean 78% right?

Answer 2

It just says 78 not 78% @mathstudent55
That's what I got confused on as well

Answer 3

Ok.
Let's look at each choice and see if we can conclude it from the given info. The one you can't conclude is the answer.

Answer 4

Ok

Answer 5

We are told A is true.

100-22=78 so C is true.

150 * 22% = 33 students absent.
150-33=117 students not absent.
33 absent - 20 boys = 13 girls absent. So B is true.

Only one left is D.

Answer 6

Choice A. There are 150 students at Smith Elementary School.

The problem starts with "Of the 150 students at Smith Elementary School..."
Obviously there are 150 students at the school.
Choice A is not it.

Answer 7

Yep, I got that

Answer 8

Choice B. 13 females were absent on Tuesday.
22% of the 150 students were absent.
22% of 150 = 0.22 * 150 = 33
33 students were absent.
Of the 33 absent students, 20 are male.
That means 13 absent students are female.
We can conclude choice B, so that's not the answer.

Answer 9

Okay. That makes sense

Answer 10

Choice C. 78% of the students were not absent on Tuesday.

If 22% of the students were absent, then 100% - 22% = 78%.
That means 78% of the students were not absent.
We can conclude choice C, so that is not the answer.

Answer 11

Yeah

Answer 12

By default, the only choice left is D, so D must be the answer. Now let's look at it just to confirm.

Answer 13

Ok

Answer 14

Choice D. 78 of the students who were not absent on Tuesday were male.

78% of the 150 students were not absent.
78% of 150 = 0.78 * 150 = 117
All we know about the students who were not absent is that there are 117 of them.
We are not told what the break down of male and female students is for the students who were not absent.
That's why we can't conclude that 78 of the present students are male.

Answer 15

That makes more sense now

Answer 16

Great.

Answer 17

Could you help me on some more questions that I don't get.

Answer 18

Sure. Just start a new post. I'll go there.

Answer 19

Thanks! :)

Answer 20

wlcm