GMAT prep division and remainder

[Felix1863]

I went through the last 13 pages of threads but could not find these. Thank you for taking the time to answer these questions again.

1) If t is a positive integer and r is the remainder when t^2+5t+6 is divided by 7, what is the value of r?

1) When t is divided by 7, the remainder is 6.
2) When t^2 is divided by 7, the remainder is 1.

2) If 2/5 of the students at College C are business majors, what is the number of female studens at College C?

1) 2/5 of the male stuents at College C are business majors.
2) 200 of the female students at College C are business majors.

Thanks again
Felix

[manish8109]

1) remainder when t^2+5t+6/7

Statement 1:

t/7 --- remainder =6
so, t could be 6,13,20,27,34 & so on

6^2+6*5+6/7 = 72/7=remainder=2
169+65+6/7 =240/7 = remainder=2
400+100 +6/7 = 506/7 = remainder=2
27^2+27*5+6/7 = remainder=2
So r=2----Sufficient

Statement 2:

t^2/7 remainder=1

so, t^2 could be 1,36,64,169 & so on
so, t could be 1,6,8,13 & so on
1+5+6/7 = remainder=5
36+30+6/7 = remainder=2

Insufficient

Ans(A)

2) Refer to
http://www.urch.com/forums/gmat-data...-students.html (Female students)