Heres a probability question.
There are 3 Republicans and 2 Democrats on a Senate committee. If a 3 person subcomittee is to be formed from this committee, what is the probability of selecting 2 Republicans and 1 Democrat?
I know that no. of ways to select 2 Rep. is 3, and that no. of ways to select 1 Dem. is 2 for 6 (3 x 2) possible ways. But how do you determine the total number of ways?(6/?)
What is the least interger greater than 999 that is divisible by 6, 8, 9?
I was able to do this question fairly quickly by trial and error but was wandering if there is perhaps a mathematical and more direct approach. (maybe prime factorization)
Use prime factorization. 6 is 2*3, 8 is 2^3, and 9 is 3^2. The find the LCM, just choose the highest power of each factor. This gives you (2^3)*(3^2) = 8*9 = 72. Thus the number must be a multiple of 72. It is simple to see that the first multiple of 72 greater than 999 is 1008.
difficult set question: a study of 400 fruit orchards showed that 250 of the orchards grew apples, 140 grew pears, 95 grew plums, 70 grew only apples and pears, 30 grew only apples and plums, 45 grew only pears and plums, and 10 grew all three.
18. how many of the orchards grew only apples or plums?
a) 30
b) 130
c) 150
d) 180
e) 345
19. How many of the orchards grew no apples, pears, or plums?
a) 0
b) 80
c) 165
d) 235
e) 320
18. the answer is a
19. I think the answer should be 50 but I dont see it as a choice?
The easiest way to solve this is to make a venn diagram with three circles. Start with the last piece of information and work your way back while filling in your chart. I'm not sure why I'm not getting an answer choice for q 19. Maybe there is a mistake.
@ Arachnotron
this is related to GRE's question about rate and time. I figured out the rates but can you explain why you did this : (27sec/90ft)(100ft) = 30 seconds.?
