Exemption u/s 10(10) of Income Tax Act....needed a solution of this question!!

Shri Rajesh was employed since 1-1-1981 in a commercial establishment. His salary was fixed at Rs.14800, in the grade of Rs. 14000-400-22000 with effect from 1-7-2016 ). He got 15%of his salary as dearness allowance which is treated salary for computation of retirement benefits. He retired from service on 1-2-2018. He recieved Rs.340000 as gratuity from his employer.
Calculate his gross income under the head 'Salaries' for the A.Y. 2018-19 if-
a) Payment of Gratuity Act, 1972 applies.
b) Payment of Gratuity Act, 1972 not applies.