Sunday’s sales are 100% = 350. Saturday is 40% fewer, so Saturday = 60% of Sunday.

SundaySaturday100% = 35060%

Plain numbers are given; italic underlined numbers are worked out.

  1. Sunday → 100% = 350 eggs
  2. 10% → 350 ÷ 10 = 35
  3. Saturday → 60% = 6 × 35 = 210
  4. Two days → 350 + 210 = 560

He sold 560 eggs over the two days.

Check: Saturday 210 is 40% (140) fewer than 350. ✓