S.2 Maths question

1.A car park charges $50 for the first 2 hours and $10 for the each additional hour.
(a) What is the average parking rate in $/h if the car is parked for 3 hours?
first 2 hours needs $50
the third hour needs $10
total amount of money=$60
average parking rate for 3 hours
=60/3
=$20

(b) Find the number of parking hours if the average parking rate is $16/h.
let h be the total number of parking hours

for the first 2 hours always needs $50
then the additional hours=(h-2) , so
[50+ (h-2)＊10]/h=16
50+ (h-2)＊10=16h
50+ 10h-20=16h
30=6h
h=5

a. The average parking rate for the car in 3 hrs:
$(50+10)/3hr
=$60/3hr
=$20/hr

Ans: The average parking rate for the car in 3 hrs is $20/hr.

b. Let the additional parking hours be x hr.
(50+x)/(2+x)=16
50+x=2+16x
15x = 18
x = 1.2

Therefore number of parking hours = (2+1.2)=3.2hrs

(a) (50+10)/3 = $20/hr

(b) Let x be the addiction hour
(50+x)/(2+x) = 16
50+x = 32+16x
15x = 18
x = 1.2
Therefore, no. of parking hours = (2+1.2)= 3.2 Hours