Question

afla numarul necunoscut (c÷9÷3)×4=20

Answer 1

$(c \div 9 \div 3) \times 4 = 20 \\ \\ (c \div 9 \div 3) = 20 \div 4 \\ \\ (c \div 9 \div 3) = 5 \\ \\ c \div 9 = 5 \times 3 \\ \\ c \div 9 = 15 \\ \\ c = 15 \times 9 \\ \\ c = 135$

Answer 2

( c : 9 : 3 ) x 4 = 20 
c : 9 : 3 = 20 : 4
c : 9 : 3 = 5
c : 9 = 5 x 3 
c : 9 = 15 
c = 15 x 9 
c = 135 

Verific:  (135 : 9 : 3 ) x 4 = ( 15 : 3 ) x 4 = 5 x 4 = 20