Nanku umzekelo wengxaki ye-mathematika: ""Ubudala bukaJohn buphinda-phinda kathathu obukaMary. Kwiminyaka emithathu ezayo, uJohn uyakube emdala ngokuphindaphindwe kabini kubudala bukaMary. Ingaba badala kangakanani uJohn noMary?"" Impendulo kule ngxaki ithi uJohn mdala ngeminyaka elu-9 abe yena uMary eneminyaka emi-3 ubudala.