Question Number 110156 by I want to learn more last updated on 27/Aug/20
$$\mathrm{If}\:\mathrm{we}\:\mathrm{have}\:\:\mathrm{5}\:\mathrm{people},\:\mathrm{how}\:\mathrm{many}\:\mathrm{ways}\:\mathrm{can}\:\mathrm{they}\:\mathrm{be}\:\mathrm{seated}\:\mathrm{in}\:\mathrm{a}\:\mathrm{row} \\ $$$$\mathrm{on}\:\mathrm{a}\:\mathrm{chair},\:\mathrm{if}\:\mathrm{their}\:\mathrm{are}, \\ $$$$\left(\mathrm{a}\right)\:\:\:\mathrm{7}\:\:\mathrm{chairs}\:\:\:\:\:\:\:\left(\mathrm{b}\right)\:\:\:\:\mathrm{3}\:\:\mathrm{chairs}\:\:\:\:\:\:\:\:\mathrm{available} \\ $$
Answered by mr W last updated on 28/Aug/20
$$\left({a}\right) \\ $$$${P}_{\mathrm{5}} ^{\mathrm{7}} =\mathrm{2520} \\ $$$$\left({b}\right) \\ $$$${P}_{\mathrm{3}} ^{\mathrm{5}} =\mathrm{60} \\ $$
Commented by I want to learn more last updated on 28/Aug/20
$$\mathrm{Thanks}\:\mathrm{sir} \\ $$