Answer: 0.4 is the single multiplier.
Explanation:
Since, If a amount is decreased by 60 % then remaining amount is (100-60)%=40% of the initial amount.
And, 40%= 40/100=0.4
Thus, when we decrease an amount by 60%,
then the resultant amount = 40% of the initial amount= 0.4 times of the initial amount.
Therefore after multiplying by 0.4 we can decrease an amount by 60%.