Answer:
step 1. 6x2=12 first place way
step 2. 12×2=24
step 3. 24+6=30 second place way
Commutative property of multiplication is shown above. This is because no matter how you put them, the answer will still be 140.
Let x be the original amount as per the ques tion (7/6) x= 420thus x=420*6/7=360thus the interest earned is 420 -360=60