Examples for 8th grade - page 112

1. Supplementary angles
One of the supplementary angles is larger by 33° than the second one. Calculate the angles size.
2. Equations - simple
Solve system of linear equations: x-2y=6 3x+2y=4
3. Poplar
How tall is a poplar by the river, if we know that 1/5 of its total height is a trunk, 1/10th of the height is the root and 35m from the trunk to the top of the poplar?
4. Two gardeners
The garden with an area of 81 square meters was divided by two gardeners in a ratio of 4: 5. How much did the second gardener get more first?
5. Together
If 8 men, 10 women, 16 children collects ₹1024 in 4 days, how many days will be required for 6 men, 5 women and 4 boys to collect ₹768? (₹ is Indian Rupee)
6. 12 apples
12 apples and 2 loaves of bread cost 5.76 and 6 apples and 3 loaves of bread cost 7.68. How much is a loaf of bread?
7. Hectoliters
How deep is the pool if there are 2025 hectoliters of water and the bottom dimensions are a = 15 meters b = 7,5 meters and the water level is up to 9/10 (nine-tenths) of height.
8. Minute average
In a factory, four workers are assigned to complete an order received for dispatching 1400 boxes of a particular commodity. Worker A takes 4 mins per box, Worker B takes 6 minutes per box, C takes 10 mins per box, D takes 15 mins per box. Find the average.
9. Perimeter of a rectangle
If the perimeter of a rectangle is 114 meters and the length is twice the width plus 6 meters, what are the length and width?
10. 40% volume
40% volume with 104 uph (units per labor hour) 8 people working. What is the volume?
11. Wave parameters
Calculate the speed of a wave if the frequency is 336 Hz and the wavelength is 10 m.
12. Intersections
Find the intersections of the function plot with coordinate axes: f (x): y = x + 3/5
13. Rectangle area
The length of a rectangle of x units is increased by 10% and its width of y units is increased by 15%. What is the ratio of the area of the old rectangle to the area if the new rectangle?
14. Mixture 2
How many liters of water must be added to 7 liters of a 20% solution to obtain a 10% solution?
15. Two equations
Solve equations (use adding and subtracting of linear equations): -4x+11y=5 6x-11y=-5
16. Taxi
A taxi ride costs \$3 plus \$2.50 per mile. Write and Graph an equation in two variables that represents the total cost of a taxi ride.