Obviously, if all the 4 inlets are used, the iPhone will be recharged in the fastest possible time.
Let, Time taken by Top, Left, Right, and Bottom inlet to individually charge the phone be represented by A, B, C, and D respectively.
Given,
1A1A + 1D1D = 120120
1B1B + 1C1C + 1D1D = 115115
1A1A + 1B1B + 1C1C = 112112
On adding all 3,
=> 2 * (1A1A + 1B1B + 1C1C + 1D1D) = 112112 + 115115 + 112112 = (15+20+25)300(15+20+25)300 = 1515
=> 1A1A + 1B1B + 1C1C + 1D1D = 110110
Therefore, all 4 together will take 10 minutes to fully charge the iphone.
The question is What is the fastest possible time in which the iphone16 can be fully charged?
Hence, the answer is 10 min.