Answer:
The correct answer is: decrease; decrease.
Step-by-step explanation:
An increase in the price of oil has increased the cost of producing ride-on lawnmowers. As the cost of production increases, at the same level of the total cost, the firm will be able to produce less quantity of mowers. This will cause a decline in the supply of mowers. The supply curve will move to the left.
At the same time, the increase in oil price will make it expensive to use mowers. This will cause a decline in demand. This will cause the demand curve to move to the left.
The equilibrium quantity will decline, the change in price will depend upon the extent of change in demand and supply.