Åk 6–9

4.5 Exercise – Changes in percent
1. Write the new value:
 a) 75 increases by 20 % b) 320 decreases by 20 % c) 110 increases by 10 % d) 800 increases by 7 % e) 140 decreases by 5 % f) 14 increases by 250 % 2. Write the percentual change:
 a) 100 decreases to 60 b) 100 increases to 160 c) 70 increases to 105 d) 970 decreases to 7 e) 40 decreases to 38 f) 18 increases to 180 3. A mobile telephone from 1996 weighed 200 g.  A year later a new model weight 85 g.  Write a mathematical expression and calculate the proportion of decrease in weight. 4. In 2002, gasoline cost 8.4 kr /l.  Today it costs 10.8 kr/l.  Write the mathematical expression and calculate the proportion of increase in price.  Round your answer to tenths. 5. A two year old child is on average 86 cm tall.  A three year old is on average 92 cm.  Write a mathematical expression and calculate the proportional increase.  Round your answer to a whole number in percent. 6. A store decreased the price of a camera from 900 kr to 783.  Write a mathematical expression and calculate the rate of change.  Round your answer to three decimals. 7. After a rain storm, the mass of a water holder increased from 10.4 kg to 13.6.  Write a mathematical expression and calculate the rate of change.  Round your answer to three decimals. 8. You deposit 30,000 kr into a savings account with a yearly interest rate of 6 %.  After 3 years, you have 35,730.  Write a mathematical expression and calculate the rate of change.