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DrSteve
Registered User Posts: **1,289** Senior Member

I thought I would start a thread of math problems that students have asked me about while preparing for their SAT. After I post each question I'll give some time for you to post your attempted solutions before providing my own. I'll try to provide the Difficulty Level and Topic for each one. Here is the first one:

Level 3 Number Theory

1. If an integer n is divisible by 15, and 25, what is the next larger integer divisible by these numbers?

(A) n + 15

(B) n + 50

(C) n + 75

(D) n + 125

(E) n + 150

Level 3 Number Theory

1. If an integer n is divisible by 15, and 25, what is the next larger integer divisible by these numbers?

(A) n + 15

(B) n + 50

(C) n + 75

(D) n + 125

(E) n + 150

## Replies to: SAT Math Problems Thread

133Junior Member1,289Senior Member124Junior Member96Junior MemberHow did I do it?

GCF x LCM= 15 x 25

GCF is for sure equal to 5.

(25 x 15)/ 5 = 75 ,so the answer is C.

1,289Senior Member@meumeu Your solution is similar. You didn't have to do quite so much work. Computing the lcm directly is just a bit quicker than computing both the product and the lcm.

1,289Senior Member1,289Senior Member2. Dana has pennies, nickels and dimes in her pocket. The number of dimes she has is three times the number of nickels, and the number of nickels she has is 2 more than the number of pennies. Which of the following could be the total number coins in Dana’s pocket?

(A) 14

(B) 15

(C) 16

(D) 17

(E) 18

2,527Senior Member4,747Senior MemberLetting p be the number of pennies, then the number of coins is p + (p+2) + 3(p+2) = 5p + 8. The number of coins must be 3 (mod 5) (i.e. 3 more than a multiple of 5) so (E) 18 is the answer.

2,527Senior Member1,289Senior MemberIf your initial guess is wrong simply adjust your guess up or down accordingly.

96Junior MemberWhen you practice any question, it is generally better to know how to do it in 2 ways.

133Junior Member2,527Senior Member66Junior Member3 men and 3 women stand in 1 line. Two or more of the same gender cannot stand next to each other. How many different arrangements are possible?