Evaporation & Percentage Decrease – A reservoir holds 500,000 litres of water. Due to evaporation, 8% of the water is lost each week. How much water remains after 3 weeks?

• 389,344 litres

• 369,343 litres

• 380,000 litres

• 379,600 litres

2. Word Problem with Algebra – The amount of rainfall in a city is modeled by the equation R = 3t² + 2t + 5, where R is the rainfall in millimeters and t is the number of weeks. How much rain falls after 4 weeks?

• Orange

• R= 72mm

• R= 76mm

• R= 61mm

Answer explanation

3. Ratio of Rainfall to Evaporation

In a certain area, the ratio of rainfall to evaporation is 3:2. If 750 mm of rain falls in a month, how much water is lost to evaporation?

• 500mm

• 150mm

• 160mm

• 555mm

Precipitation and Evaporation:

A snow squall drops 16 out of 20 units of snow. The sun shines brightly, melting snow at a rate of 1/16 per minute for 10 minutes. How much snow melts, and how much is left?

• 29/40 snow melted

  29/40 snow remained

• 26/40 snow melte

  84/40 snow remained

• 25/40 snow melted

  7/40 snow remained

• 22/40 snow melted

  14/40 snow remained

Runoff and Precipitation: Rain falls for 28 minutes at a rate of 2/42 units per minute. A pool, currently 1/8 full, collects some of the rain. How much water runs off instead of staying in the pool?

• 11/23

• 11/24

• 12/30

• 13/30

Runoff, Power of numbers

Simply the following expressions and find for the runoff:

Rain fallen= 3*2 × 3*4

Bucket filled= 1/2 of 16ml.

Formula: Runoff= rain fallen- bucket filled

• 720 ml

• 780 ml

• 790 ml

• 721 ml

Precipitation

Last Wednesday, 0.76 units of rain fell and this Wednesday 0.49 fell. Find the difference between these two decimals and write it as a fraction.

• Purple

• 27/50

• 29/200

• 27/100

If 3 litres of rain fell on Sunday and for the rest of the week it poured 3 times as much. How many litres of rain fell for the whole week?

• 57 litres

• 47 litres

• 30 litres

• 41 litres

If a lake has 4000 miles of water and the sun evaporated 3/4 how many miles of lake is left?

• 3500 miles

• 3000 miles

• 600 miles of open sea

• 1000 miles

If 65% of humidity is needed for condensation to occur, and during Sunday to Friday, only 35% was made. Then calculate how much more humidity is needed for condensation to occur.

• 50%

• 30%

• 40%

• 37%