Question

Maria a cumparat de la cofetarie doua amandine si trei ecleuri pentru care a platit 24 lei,iar prietena ei,Ioana, a cumparat doua amandine si sapte ecleruri care au costat 40 lei. Cat costa un ecler? Dar amandina?

Answer 1

a=amandine; e=ecler
2a+3e=24
2a+7e=40

2a+3e=24
2a=24-3e

24-3e+7e=40
4e=40-24=>4e=16
e=16:4=>e=4

2a+3e=24
2a+(3×4)=24
2a+12=24
2a=24-12
2a=12=>a=12:2=>a=6

2×6+3×4=24
12+12=24
24=24

2×6+4×7=40
12+28=40
40=40
deci: 1 amandina costa 6 lei si 1 ecler costa 4 lei