GRE Exam Numerical Ability Time and Work

Question
Working alone at its constant rate, machine A produces k car parts in 10 minutes. Working alone at its constant rate, machine B produces k car parts in 15 minutes. How many minutes does it take machines A and B, working simultaneously at their respective constant rates, to produce k car parts?

Read Solution (Total 2)

A=k/10
B=k/15

working togeather=A+B
=k/10+k/15
=k/6

Ans : 6min
6 years agoHelpfull: Yes(0) No(0)

A-10
B-15
lcm of a and b is 30
a=30/10=3;b=30/15=2;
a+b=30/5=6 mins.
5 years agoHelpfull: Yes(0) No(0)

GRE Other Question

ANNUAL PERCENT CHANGE IN DOLLAR AMOUNT OF SALES AT FIVE RETAIL STORES FROM 2006 TO 2008)
Store --- Percent 2006-7 --- Percent 2007 8
P ------------- 10 ---------------------- –10
Q ------------ –20 --------------------- 9
R ------------- 5 ----------------------- 12
S ------------- –7 ----------------------- –15
T ------------- 17 ----------------------- –8

Question 1
At Store T, the dollar amount of sales for 2007 was what percent of the dollar amount of sales for 2008? Give your answer to the nearest 0.1 percent.

Question 2
If the dollar amount of sales at Store P was $800,000 for 2006, what was the dollar amount of sales at that store for 2008 ? a $727,200 b $792,000 c $800,000 d $880,000 e $968,000

Question 3
Based on the information given, which of the following statements must be true? Indicate all such statements.
(a) For 2008 the dollar amount of sales at Store R was greater than that at each of the other four stores.
(b) The dollar amount of sales at Store S for 2008 was 22 percent less than that for 2006.
(c) The dollar amount of sales at Store R for 2008 was more than 17 percent greater than that for 2006. Question
Rectangle R has length 30 and width 10, and square S has length 5. The perimeter of S is what fraction of the perimeter of R ?