Question

Answer 1

a/=6/7x(4/10+3/10)

=6/7x7/10

=42/70=6/10

b/2/5x(3/7+4/7)

=2/5x1

=2/5

Answer 2

a, C1 6/7 x ( 4/10 + 3/10)

= 6/7 x 7/10

= 6/10 

= 3/5

C2 6/7 x 2/5 + 6/7 x 3/10

= 12/35 + 18/70

= 24/70 + 18/70

= 42/70

= 3/5

b, C1 2/5 x 3/7 + 2/5 x 4/7 

= 2/5 x (3/7 + 4/7)

= 2/5 x 1

= 2/5

C2 2/5 x 3/7 + 2/5 x 4/7

= 6/35 + 8/35

= 14/35

= 2/5

Answer 3

mẹ mua số kg gạo tẻ là

105x4/5=84(kg)