An arborist is preparing the fuel mix for her chainsaw before

climbing a tree to remove a dead limb$.$ The$$ two$-$stroke chainsaw

requires a $5\%$ mix of engine oil to gas$$that $$is$,$ the amount of oil

should be $5\%$ of the amount of gas. How much engine oil should be

added to a jerry can that contains $2\mathrm{.}5$ gallons of$$ gas?