4 times with a remainder of 10
9 times
15 goes into 1050 seventy times
5
4 times with a remainder of 10
84 times.
Twice
70 times.
11 times with 3 left over
1 goes into 4 four times.
9 with remainder 40.
No, that is a very bad substitute. If you want to go with a 70 series tire go with a 195/70-15 which is a great substitute.
66 goes into 70 1.06060606 times