Answer:
Q.no.1
d=1 then t=7
d=3 then t=11
t=15 then d=5
Q.no.2
d=1 then t=3
d=3 then t=9
Q.no.3
5x = 12+18
or, 5x = 30
or, x =30/5
or, x = 6
Q.no.6
x < 8
Q.no.7
x >_ 7 ( option d)
Hope it helps.
4.5m questions
5.8m answers