Question

ACT PREP Q: if 5 times a number n is subtracted from 15, the result is negative. Which of the following gives the possible value(s) for n?

Answer 1

@Vocaloid

Answer 2

0 only
3 only
10 only
all n greater than 3
all n less than 3
ANSWER CHOICES

Answer 3

"negative" means less than 0, so

15 - 5n < 0
know where to go from here?

Answer 4

would you add 15 to the other side?

Answer 5

subtract

Answer 6

so we would then have -5n less than -15?

Answer 7

yes, do you know what to do next?

Answer 8

divide!

Answer 9

so would n=3?

Answer 10

almost but not quite

so we have -5n < -15
divide both sides by -5 gives us

n > 3 (remember, when we divide or multiply by a negative number, the inequality sign flips direction)

Answer 11

15<3n
or3n>15
?

Answer 12

so n greater than 5?

Answer 13

3

Answer 14

n > 3

Answer 15

ok so the answer would then be all n greater than 3?

Answer 16

yes

Answer 17

okay! one more question ??? @Vocaloid

Answer 18

sure, post away ~

Answer 19

ok, should i create a new Q?

Answer 20

yes