If the price of petrol is increased by $20 \%$,by what percentage should the consumption be decreased by the consumer,if the expenditure on petrol remains unchanged (in $\%$)?

Sashi has $Rs. 90000$ with him. He purchases a mobile,an iPad,and a laptop for $Rs. 15000$,$Rs. 13000$,and $Rs. 35000$ respectively and puts the remaining money in his bank account which pays $15 \%$ per annum compound interest. After $2$ years,he sells off the three items at $80 \%$ of their original price and also withdraws his entire money from the bank by closing the account. What is the total percentage change in his assets (in $\%$)?

In a motor of $120$ machine parts,$5 \%$ parts were defective. In another motor of $80$ machine parts,$10 \%$ parts were defective. For the two motors considered together,the percentage of defective machine parts was (in $\%$)

Two numbers are respectively $20 \%$ and $30 \%$ less than a third number. What is the second number as a percentage of the first?

$4598$ is $95 \%$ of what number?

$3.5$ can be expressed in terms of percentage as