Repeat Prob. 138 with a 25 pressure angle. To avoid the problem of interference in a pair

Question:

Repeat Prob. 13–8 with a 25◦ pressure angle.
To avoid the problem of interference in a pair of spur gears using a 20◦ pressure angle, specify the minimum number of teeth allowed on the pinion for each of the following gear ratios.
(a) 2 to 1
(b) 3 to 1
(c) 4 to 1
(d) 5 to 1