Are you sure about your solves??
I think correct answer is 6,
I don't know but the standard way is in the photo:
Answer:
1 3/10
Step-by-step explanation:
Find the common denominator.
6/15 times 2
12/30
3/10 times 3
9/30
3/5 times 6
18/30
Add.
12/30 + 9/30 + 18/30 = 39/30
Simplify
13/10 = 1 3/10
Answer:
160 Seconds or 2 minutes and 45 seconds
Step-by-step explanation: So 6.4x25=160 seconds or 2 min 45 sec