Item 16 Explain why a change from 20 to 40 is a 100% increase, but a change from 40 to 20 is a 50% decrease. Increasing 20 to 40 is the same as increasing 20 by . So, it is a 100% increase. Decreasing 40 to 20

Harry owes the bank money. to repay his debt, he paid $150 back to the bank each month. after 10 months, his remaining debt was $6900. what was the original amount of harry's debt? how long did it take harry to pay back his entire debt?