Question

a + b = 300
b = c x 9
c = e : 6
e : 6 = 19

a x b = 90
b =c x 3
c = d :10
d-e= 250
e:10 = 5

Answer 1

a+b=300
b=9c
c=e:6
e:6=19
e=19×6
e=114
c=e:6
c=114:6
c=19
b=9c
b=9×19
b=171
a+b=300
a+171=300
a=300-171
a=129

a×b=90
b=3c
c=d:10
d-e=250
e:10=5
e=5×10
e=50
d-e=250
d-50=250
d=250+50
d=300
c=d:10
c=300:10
c=30
b=3c
b=3×30
b=90
a×b=90
a×90=90
a=90:90
a=1