Ake sixazulule inkinga elandelayo yezibalo. Unogwaja ngamunye unemilenze emine kanti idada ngalinye linemilenze emibili. Uma kunezinhloko ezingu-25 nezinyawo ezingu-88, zingaki onogwaja namadada akhona?
Singasebenzisa ama-equation ukuxazulula le nkinga. Inani lamadada makabe ngu-X nenani lemvubelo makabe ngu-Y. X + Y = 25 (1) 2X + 4Y = 88 (2). Kusuka ku equation yokuqala, siyazi ukuthi X = 25-Y futhi singafaka lokhu ku equation yesibili (2), futhi sithola 2(25-Y) + 4Y = 88 Okungase kwenziwe kube lula ku 50 + 2Y = 88 futhi sine Y = 19. Sifaka inani ku (1), sizothola u-X = 6. Kukhona amadada ayisithupha nonogwaja abangu-19!