42,48,60,66,78---

Dear Rishabh
4+2=6

Now 42+6=48

48 becomes 4+8=12

Now 48+12=60

60 becomes 6+0=6

Now 60+6=66

66 becomes 6+6=12

Now 66+12=78

78 becomes 7+8=15

Now 78+15=93
Sometimes,  we need to think in a creative way.
There are almost 7 methods to find the next number in the number series.
Every time,  any one method is enough to find the missing one.
All the best.