Answer :
a=24+b
c=4a
c=4(24+b)
a+b+c=180
24+b+b+4(24+b)=180
24+b+b+96+4b=180
120+6b=180
6b=60
b=10
a=24+10
a=34
c=4(34)
c=136
34+10+136=180
So book a has 34 pages, book b has 10 pages, and book c has 136 pages.
c=4a
c=4(24+b)
a+b+c=180
24+b+b+4(24+b)=180
24+b+b+96+4b=180
120+6b=180
6b=60
b=10
a=24+10
a=34
c=4(34)
c=136
34+10+136=180
So book a has 34 pages, book b has 10 pages, and book c has 136 pages.
a=b+24
c=4a
b=a-24
a+b+c=180
sub in a,b and c into a+b+c=180
b+24+4a+a-24=180
b+5a=180
sub a=b+24
b+5(b+24)=180
b+5b+120=180
6b=180-120
6b=60
b=10
Book B has 10 pages
c=4a
b=a-24
a+b+c=180
sub in a,b and c into a+b+c=180
b+24+4a+a-24=180
b+5a=180
sub a=b+24
b+5(b+24)=180
b+5b+120=180
6b=180-120
6b=60
b=10
Book B has 10 pages