math
posted by dawn .
the least common multiple of 3, 6,9 i say 18
Sheila practiced hours Monday, hours Tuesday, and hours Wednesday. What is the total number of hours that she practiced?
A) hours B) hours C) hours D) 6 hours
Complete the statement, using the symbol < or >.
0.6
A) > B) <
Jon spent of his study time doing math homework and preparing for a history exam. What fraction of his study time remains?
A) B) C) D)

Your first answer is correct.
But, you seem to have left out important information in the other two questions. 
1 1/2 hours 3 3/4 2 1/4 the anwers you can chose from are
a. 7 1/2 hours
b. 5 1/4
c. 8 1/2 hours
d. 6 hours 
1 1/2 + 3 3/4 + 2 1/4 =
1 2/4 + 3 3/4 + 2 1/4 = 6 6/4 = 7 1/2 
jon spent 1/3 of his time 2/7 preparing the following you can chose from A) 13/21 B) 5/21 C) 1/21 D) 8/21

1/3 + 2/7 = 7/21 + 6/21 = 13/21
21/21  13/21 = ??