Answer:
In month 4 they will have the same amount of money.
Explanation:
An: Starting w/ 160 + 50 = 210
add 50 again month 2 =260
Add 50 again month 3 =310
Add 50 again month 4 =360
Shen: Starting w/ 0 + 90 = 90
add 90 again month 2 = 180
Add 90 again month 3 =270
Add 90 again month 4 = 360