Answer : 
Explanation:
Since we have given that
n(U) = 120, where U denotes universal set ,
n(F) = 45, where F denotes who speak French,
n(S) = 42 , where S denotes who speak Spanish,
n(F∪S)' = 50
n(F∪S) = n(U)-n(F∪S) = 120-50 = 70
Now, we know the formula, i.e.
n(F∪s) = n(F)+n(S)-n(F∩S)
⇒ 70 = 45+42-n(F∩S)
⇒ 70 = 87- n(F∩S)
⇒ 70-87 = -n(F∩S)
⇒ -17 = -n( F∩S)
⇒ 17 = n(F∩S)

Answer:
1. 10% of the bill is $138. The final bill once 10% is taken off is $1242.
2. 20% of the total is $34.10. The final total once the 20% is taken off is $136.4
Step-by-step explanation:
1. A crash repair bill comes to $1380.00. How much is 10% of the bill? What is the final bill once 10% is taken off?
To find how much is 10% of the bill, we multiply the bill by 0.1
0.1*1380 = 138
10% of the bill is $138.
To find the final bill, we subtract the initial bill by 10%.
1380 - 138 = 1242
The final bill once 10% is taken off is $1242.
2. A person buys a new fan belt, a new alternator, and a new water pump for their car. The total comes to $170.50. What is 20% of the total? How much is the final total once the 20% is taken off?
Same logic as above.
0.2*170.50 = 34.1
20% of the total is $34.10.
170.50 - 34.1 = 136.4
The final total once the 20% is taken off is $136.4