Question

a:20=40*3... 210:с=420:6...

Answer 1

а:20=40*3

а=20*40*3=2400

 

210/с=420/6

70с=210

с=3

Answer 2

$a:20=40cdot3$

 

$a:20=120$

 

$a=120cdot20$

 

$a=2400$

______________________________________

$2400:20=40cdot3$ (это проверка)

 

$120=120$

======================================

$210:c=420:6$

 

$210:c=70$

 

$c=210:70$

 

$c=3$

______________________________________

$210:3=420:6$

 

$70=70$