Question Number 182705 by HeferH last updated on 13/Dec/22
$${A}\:{father}\:{has}\:\$\mathrm{320}\:{to}\:{go}\:{a}\:{sporting}\:{event}\:{with} \\ $$$$\:{his}\:{children}.\:{If}\:{he}\:{takes}\:{tickets}\:{of}\:\$\mathrm{50}\:{he} \\ $$$$\:{lacks}\:{money},\:{if}\:{he}\:{takes}\:{tickets}\:{of}\:\$\mathrm{40}\:{he} \\ $$$$\:{has}\:{money}\:{left}\:{over}.\:{Find}\:{the}\:{number}\:{of}\: \\ $$$$\:{children}. \\ $$
Answered by Rasheed.Sindhi last updated on 13/Dec/22
$${Let}\:{number}\:{of}\:{persons}={x} \\ $$$$\mathrm{50}{x}>\mathrm{320}\:\wedge\:\mathrm{40}{x}<\mathrm{320} \\ $$$${x}=\left\{\mathrm{7},\mathrm{8},...\right\}\:\cap\:\left\{\mathrm{1},\mathrm{2},...\mathrm{7}\right\} \\ $$$${x}=\mathrm{7} \\ $$$${The}\:{father}\:{has}\:\mathrm{6}\:{children}. \\ $$