When Minjun was late, he went to school at 15 kilometers (km) per hour, and when he came back at a leisurely pace of 10 kilometers (km) per hour, it took 30 minutes longer than when he went to school. How long did it take to go to school?
10 30 60 [OP_DIV] [OP_MUL] 15 10 [OP_SUB] [OP_DIV]
var_a = 10
var_b = 30
var_c = 60
var_d = var_b / var_c
var_e = var_a * var_d
var_f = 15
var_g = 10
var_h = var_f - var_g
var_i = var_e / var_h
print(int(var_i))