prima lada /---------/
a doua lada /--------/---------/---------/
a treia lada /--------/----------/----------/ + inca 10 kg
871 kg -10 kg=861 kg - 7 segmente egale
871 kg : 7 = 123 kg - prima lada
123kg x 3= 369 kg - adoua lada
369 kg + 10 kg = 379 kg - a treia lada