A ton is 2,000 pounds so multiply 2,000 x 18
2,000 x 18 = 36,000 pounds, now add the 42 pounds to the 36,000
36,000 + 42 = 36,042 pounds. Now divide 36,042 by 3
36,042 ÷ 3 = 12,014
Your answer is 12,014 pounds
If you need your answer in tons it's 6.007 tons
Calculations for pounds to tons
12,014 ÷ 2,000 = 6.007
Hope this helps. :)