04 Try it yourself Interactive

Men, days, hours and work

Set the first job and the second job’s conditions. The console totals the man-hours, reduces to a per-unit figure, scales up and divides — then shows the same answer as a single product of ratios so you can see which way up each one sits. Change one input at a time and check the direction of the movement matches the table above.

28 men, 10 houses, 5 d, 4 h → 15 houses, 6 d, 10 h
14 men
Work is direct; days and hours are inverse. The final step lays out all four ratios so the placement is visible rather than remembered.
Press Next to work through it one step at a time.
Man-hours–
Per unit–
Needed–
Men–
step 0 / 0