Question

How many minutes he does arm routine and abdominal routine​

Answer 1

Answer:-

Let x be the amount of time it takes to perform an arm routine and y be the amount of time it takes to perform an abdominal routine.

We see:

4x+y=704x+y=70

4x+2y=1004x+2y=100

Subtracting the second equation from the first gives y=30y=30 .

Substituting gives

4x+30=704x+30=70 ,

so

4x=404x=40 and x=10x=10 .

Thus, an arm routine takes ten minutes and an abdominal routine takes thirty minutes.

Answer 2

Answer:

Answer

Let

Let The time needed for arm routine be “a” and abdominal routine be “ b”

So now

So now We will make equation of both

So now We will make equation of bothTherefore,

So now We will make equation of bothTherefore, According to first condition

So now We will make equation of bothTherefore, According to first condition 4a +b=70

And also according to second condition

4a+2b=100

No we have two equation

We can find the vaule of a, b by three

Method

That is

1) substitution method

2) Elimination method

3) cross multiplication method

We will solve this by Elimination method

4a +b=70

4a+2b=100

- - = -

We have change the sign of second equation

Therefore

4a +b=70.................... (equation 1)

-4a-2b=-100

Therefore

- b=-30

b=30

Put b =30 in equation 1

4a+30=70

4a=70-30

4a=40

a=10

We got a=10 and b =30

Therefore

The time needed for arm routine is 10 min.

The time needed for abdominal routine is 30 min.