Answer:
The amount of time he spent on the bicycle using substitution method is 4.5 hours .
Step-by-step explanation:
The unitary method is a technique for solving a problem by first finding the value of a single unit, and then finding the necessary value by multiplying the single unit value.
A linear equation is defined as an equation that is written in the form of Ax+By=C. It is the combination of two variables and a constant value present in them.
The first step in the substitution method is to find the value of any one of the variables from one equation in terms of the other variable.
Let the total time taken to complete the race by bicycle be x
Let the total time taken to complete the race by walking be y
We know,
Speed=Distance/Time
4y+30x=145
x+y=7
Using the substitution method ,
x=7-y
4y+30(7-y)=145
4y+210-30y=145
210-145=26y
y=65/26
y=2.5
So, the amount of time he spent on bicycle is x
x=7-y
x=7-2.5
x=4.5 hours
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