jim weighs more than joe but less than jack. Their weights in kilograms are consecutive by multiples of 7. If they each weighed 5kg less, the sum of their weights is 195kg

Joe: 7k

Jim: 7 (k+1)

Jack: 7 (k+2)

(7k-5) + (7 (k+1) - 5) + (7 (k+2) - 5) = 195

(7k-5) + (7k+2) + (7k + 9) = 195

21k + 6 = 195

21k = 189

k = 9

Joe: 7k = 7 (9) = 63

Jim: 7 (k+1) = 7 (9+1) = 7 (10) = 70

Jack: 7 (k+2) = 7 (9+2) = 7 (11) = 77

Answer: Joe=63kg, Jim=70kg, Jack=77kg