By what percentage pressure of a gas has to be changed to decrease its volume by 20% at constant temperature

let initial volume V1=100⇒final volume is V2=80; boyles law is PV=constant;P is pressure ⇒P2V2=P1V1⇒P2P1=V1V2=10080=108=54 ⇒P2 P1−1=54−1⇒P2 P1−1100=14100=25⇒percentage change in pressure of gas isΔPP×100=14×100=25%increase