Let the consecutive even numbers be A = 2x, B = 2x + 2, C = 2x + 4, D = 2x + 6 and E = 2x + 8= A + B + C + D + E = 130= 10x + 20 = 130∴ x = 130 - 20/10 = 11Therefore, product of A and E= 22 x 30 = 660
Let the price of a pen be 'x' and that of pencil be 'y' Then 87x + 29y = 783Multiplying eqn (i) by 30/29 we get (87x) x 30/29 + (29y) 30/29 = 783 x 30/29∴ 90x + 30y = 810
Let the ten's digit be x and unit's digit be y. Then, number 10x + y.Number obtained by interchanging the digits = 10y + x.(10x + y) + (10y + x) = 11(x + y)which is divisible by 11.