a book seller sold a book for $100 and thereby gains $20. Find his gain per cent a) 20% b) 25% c)40% d) none of the above. plz i need help asap​

a.20%

Step-by-step explanation:

because of the book is 100$ and the thereby sold it and gained 20$ equals to 20%

b

step-by-step explanation:

none.

step-by-step explanation:

m

1

=

5

m1=5

b

=

−

1

b=-1

find the slope and y-intercept of the second equation.

tap for more

m

2

=

0

m2=0

b

=

−

6

b=-6

compare the slopes

m

m of the two equations.

m

1

=

5

,

m

2

=

0

m1=5,m2=0

compare the two slopes in the decimal form. if the slopes are equal, then the lines are parallel. if the slopes are not equal, then the lines are not parallel.

m

1

=

5

,

m

2

=

0

m1=5,m2=0