Examples for 9th grade - page 26
- Washing mashine
Family buy a washing machine for 350e. Cash paid 280e. What percentage of the total price must still pay the washer?
- Hydrochloric acid
Determine the concentration of which must have a solution of hydrochloric acid that mixing 10 l of the solution with 8 liters of 26% solution to get the solution with a concentration of 50%?
- Water reservoir
The water reservoir is filled with one pump for 4 days by the second one for 9 days. Outlet can drain tank in 12 days. How long take fill the reservoir if both pumps are running and not closed outlet channel.
From 55% and 80% spirit we would like to produce 0.2 kg of 60% spirit. How many of them we must use in a solution?
- Water level
The glass container has a cuboid shape with dimensions of the bottom 24 cm and 12 cm. The height of water is 36 cm. Calculate the volume of the body, which are sunk into the water if the water level rise by 3 cm.
Two members will make profit 52 000, - EUR. The forst earned 8% more and the second 10% more and thus earned together 56 700, - EUR. How many will initially each earn?
Theatrical performance was attended by 480 spectators. Women were in the audience 40 more than men and children 60 less than half of adult spectators. How many men, women and children attended a theater performance?
- Painting school
Redecoration school had scheduled for four crew to 10 days. After two days a single worker ill. For how many days the school was painted when remain workers working with the same tempo?
120 vehicles parking on the morning. Pasenger car is charged 20 CZK, 50 CZK per bus. The guard collected for parking 2640 CZK in total. How many cars and how many buses stood in the parking?
- Mushrooms from the forest
Magda and Tereza goes to pick mushrooms. Total found 70 mushrooms. Magda found that between fungi found 5/9 bedel. Tereza discovered that she found among fungi are 2/17 champignons. How many mushrooms found Magda?
- Parallelogram ABCD
The area of parallelogram ABCD is 41 cm2. Points M and N are the midpoints of the sides AB and BC. What is the area of a quadrilateral MBND?
Area of circle inscribed in a square is 6. What is the area of a circle circumscribed around a square?
- Nuts, girl and boys
Milena collected fallen nuts and called a bunch of boys let them share. She took a condition: the first boy takes one nut and tenth of the rest, the second takes 2 nuts and tenth new rest, the third takes 3 nuts and tenth new rest and so on. Thus managed.
Pizza with a diameter 41 cm have weight 531 g. What diameter will have a pizza weighing 749 g if it is make from the same cloth (same thickness....) and same decorated?
- Task of the year
Determine the number of integers from 1 to 106 with ending four digits 2001.
The top of the tower is a regular hexagonal pyramid with base edge 9.2 meters long and a height 9.6 meters. How many m2 of sheet is required to cover the top of the tower if we count 12% of the sheet waste?
Cylinder was drawn in scale 7:1. How many times is the volume of the cylinder smaller in reality?
- Simple interest 2
Find the simple interest if 2531 USD at 2.5% for 9 months.
The top of a lighthouse is 12 m above the sea. How far away is an object which is just “on the horizon”? [Assume the earth is a sphere of radius 6378.1 km.]
Three metal balls with volumes V1=41 cm3 V2=58 cm3 and V3=83 cm3 melted into one ball. Determine it's surface area.