Answer:
Step-by-step explanation:
You are going to choose 4 books in any order.
Four = 12! /(8!4!)    Remember that order doesn't matter, so we have 12C4
495
 
        
             
        
        
        
Answer: She invested $12000 in fund B.
Step-by-step explanation:
Let x represent the amount which she invested in fund A.
Let y represent the amount which she invested in fund B.
The amount she invested in Fund A was twice as much as the amount she invested in fund B. This means that 
x = 2y
Fund A returned a 7% profit. It means that the profit returned from fund A is 
7/100 × x = 0.07x
Fund B returned a 5% profit. It means that the profit returned from fund B is 
5/100 × y = 0.05y
if total profit from the two funds together was $2280, it means that 
0.07x + 0.05y = 2280- - - - - - - - - - -1
Substituting x = 2y into equation 1, it becomes
0.07 × 2y + 0.05y = 2280
0.14y + 0.05y = 2280
0.19y = 2280
y = 2280/0.19
y = 12000
x = 2y = 2 × 12000
x = 24000
 
        
             
        
        
        
Answer:
95
Step-by-step explanation:
step 1
Find out the total ball bearing ordered
Multiply the number of ball bearing boxes by the number of ball bearings in each box.

step 2
Find out the total springs ordered
Multiply the number of spring boxes by the number of springs in each box.

step 3
To find out how many more ball bearings than  springs did they order, subtract the total number of springs from the total number of ball bearings

 
        
             
        
        
        
Answer:
55
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
1231.5
Step-by-step explanation:
I hope this help.