(4) A taxi service charges Rs.100 as an initial fee and Rs.50 for each kilometer travelled. Write an algebraic expression for the total amount that has to be paid for a journey of x meters.

Answer:
f(x) = 50x + 100
Explanation:
The term "Rs. 100" is constant. The term "Rs. 50" keeps changing per km.
Linear equation: y = mx + b, where 'm' is rate of change, 'b' is constant
Equation built:
f(x) = 50x + 100
This will determine the cost for journey of x meters.