The table below shows the weekly demand and supply schedules for organic avocados in a regional market.
| Price per box (£) | Quantity demanded (thousand boxes per week) | Quantity supplied (thousand boxes per week) |
|---|---|---|
| 20 | 80 | 200 |
| 17 | 105 | 170 |
| 14 | 140 | 140 |
| 11 | 180 | 110 |
| 8 | 230 | 70 |
The market was initially in disequilibrium with a shortage of 70 thousand boxes per week, but subsequently adjusted and moved to equilibrium. What was the change in the quantity supplied (in thousand boxes per week)?
−40-40−40
−30-30−30
+30+30+30
+40+40+40
