*Solution* Universal set = { set of integers greater or equal to 10 but less or equal to 100 } A = { multiples of 17 within the universal set } A = { 17, 34 ,51, 68, 85 } B = { 15×1+7 ; 15 × 2 + 7, 15× 3 + 7; 15 × 4 + 7; 15 × 5 +7 ; 15× 6 + 7 } B = { 22, 37, 52 , 67, 82 , 97} *Answers* ( i ) number of elements in A. n ( A ) = 5 ( ii ) Largest element of B is 97 ( iii ) ( A u B ) = { 17, 22, 34 , 37, 51, 52, 67, 68, 82, 85, 97 } n ( A u B ) = 11 n ( A u B ) means elements which are in A or B ( or in both A and B )