Zeros at the end means multiple of 10, i.e. (2 × 5).

•  Now, 1 × 5 × 10 × 15 × 20 × 25 × 30 × 35 × 40 × 45 × 50 × 55 × 60 = 1 × 5 × (5 × 2) × (5 × 3) × (5 × 22) × (5 × 5) × (5 × 3 × 2) × (5 × 7) × (5 × 23) × (5 × 9) × (5 × 5 × 2) × (5 × 11) × (5 × 22 × 3)

•  Here, number of 2s = 10

•  And number of 5s = 14

•  The lesser of the two will determine the number of zeros.

•  Hence, there will be 10 zeros at the end in the given expression.