Thread: 6th grade math help

Corey’s parents agree to loan Corey $182 to help pay
for the school’s spring music trip to Florida. Corey agrees to
monthly payback amounts of $2, $4, $6, $8, and so on. How long
will it take Corey to pay back the $182?

Please help!

Originally Posted by GNUF3

Corey’s parents agree to loan Corey $182 to help pay
for the school’s spring music trip to Florida. Corey agrees to
monthly payback amounts of $2, $4, $6, $8, and so on. How long
will it take Corey to pay back the $182?

Please help!

Can Corey pay any amount on that list? That is to say, can he pay $8 one month and then $2 the next or do they have to be paid in that order $(2, 4, 6, etc)?

-Dan

Sn = 2 + 4 + 6 + 8 + ... = 182
2(1 + 2 + 3 + ... n) = 182
2n(n + 1)/2 = 182
n(n + 1) = 182
182 = 2 × 7 × 13 = 13 × 14
n = 13
in 13 months Corey to pay back the $182
----

GNUF3, do you understand that you could have done this with a few minutes of integer arithmetic?
2+ 4= 6
6+ 6= 12
12+ 8= 20
20+ 10= 30
30+ 12= 42
42+ 14= 56
56+ 16= 72
72+ 18= 90
90+ 20= 110
110+ 22= 132
132+ 24= 168
That's now 182- 168= $14
So there are those 11 payments and a twelfth payment of $14.

Originally Posted by HallsofIvy

GNUF3, do you understand that you could have done this with a few minutes of integer arithmetic?
2+ 4= 6
6+ 6= 12
12+ 8= 20
20+ 10= 30
30+ 12= 42
42+ 14= 56
56+ 16= 72
72+ 18= 90
90+ 20= 110
110+ 22= 132
132+ 24= 168
That's now 182- 168= $14
So there are those 11 payments and a twelfth payment of $14.

The first step should be 0+2=2 as $2 is the first installment.
also, the second last step should be 132+24=156 and hence the number of months needed is 13, not 12.

Thanks all for your help!

There are help tips on gwl10925's profile and a good book for 6th grade at 6th Grade Math by Jessica Corriere Robert Richards (Paperback) - Lulu