She has 4 groups all together. 3 groups with ten rocks each and 1 group with 8 rocks(8/10).
-3n+48=0
-3n=-48
-3n/-3 & -48/-3
n=16
Answer:
The expectation is 
Step-by-step explanation:
From the question we are told that
The first offer is 
The second offer is 
The third offer is 
The number of tickets is 
The price of each ticket is 
Generally expectation is mathematically represented as

given that they just offer one
Now
given that they just offer one
Now
given that they offer five
Hence the expectation is evaluated as


Now given that the price for a ticket is 
The actual expectation when price of ticket has been removed is


Answer:
C (48)
explanation:
firstly, divide 384 by 80. This gives you 4.8. So, since 10 out of every 80 students are left handed we have to times 4.8 by 10 which gives you 48.