If in a coding language CORONA is written as 3151815141, how will MASK be written in that coding language?
If in a coding language CORONA is written as 3151815141, how will MASK be written in that coding language?
Each letter is replaced by its position number in the alphabet and the numbers are joined together: C=3, O=15, R=18, O=15, N=14, A=1, giving 3-15-18-15-14-1, which joined is 3151815141 (matching the given code). For MASK: M=13, A=1, S=19, K=11, joined gives 1311911.
Re-check your working by substituting the answer back into the original question.