# Expression of a variable from the formula + time - math problems

#### Number of problems found: 93

• The projectile The projectile was fired horizontally from a height of h = 25 meters above the ground at a speed of v0 = 250 m/s. Find the range and flight time of the projectile.
• Fighter A military fighter flies at an altitude of 10 km. From the ground position, it was aimed at an altitude angle of 23° and 12 seconds later at an altitude angle of 27°. Calculate the speed of the fighter in km/h.
• Compound interest 4 3600 dollars is placed in an account with an annual interest rate of 9%. How much will be in the account after 25 years, to the nearest cent?
• Age of family The age of father and son is in the ratio 10: 3. The age of the father and daughter is in ratio 5: 2. How old are a father and a son if the daughter is 20?
• Growth of wood The annual growth of wood in the forest is estimated at 2%. In how many years will make the forest volume double?
• Motion The two bodies move in the same direction evenly in a straight line, at speeds of 5 cm/s and 10 cm/s. The movement of the first body started 2 seconds earlier than the movement of the second body, from a point located at a distance of 20 cm from the start
• The farmer The farmer calculated that the supply of fodder for his 20 cows was enough for 60 days. He decided to sell 2 cows and a third of the feed. How long will the feed for the rest of the peasant's herd last?
• Volume per time How long does fill take for a pump with a volume flow of 200 l per minute fill a cube-shaped tank up to 75% of its height if the length of the cube edge is 4 m?
• Up and down motion We throw the body from a height h = 5 m above the Earth vertically upwards v0 = 10 m/s. How long before we have to let the second body fall freely from the same height to hit the Earth at the same time?
• Maxwell’s inductance bridge The four arms of Maxwell’s inductance bridge are; Arm AB contains an Inductive coil of inductance L1 having resistance R1. Arms BC and CD contain non-inductive resistances of 200Ω and 100Ω respectively. Arm AD contains standard inductor of inductance L2 a
• Workers 9 If two workers fix two windows in an hour how many windows can 18 workers fix in the same two windows?
• Six painters Six painters paint an area of 120 m2 in 4 hours. How long does it take for 12 painters to paint 480 m2 with the same performance?
• Hectares of forest 12 workers plant 24 ha of forest in 6 days. In how many days will 15 people and 12 people plant the same area?
• Volume of wood Every year, at the same time, an increase in the volume of wood in the forest is measured. The increase is regularly p% compared to the previous year. If in 10 years the volume of wood has increased by 10%, what is the number p?
• Greg and Bill Greg is 18 years old. He is 6 less than 4 times Bill's age. How old is Bill?
• Savings The depositor regularly wants to invest the same amount of money in the financial institution at the beginning of the year and wants to save 10,000 euros at the end of the tenth year. What amount should he deposit if the annual interest rate for the annua
• What is What is the annual percentage increase in the city when the population has tripled in 20 years?
• Where and when The truck left Kremnica at 11:00 h at a speed of 60km/h. At 12:30 h, the passenger car started at an average speed of 80km/h. How many kilometers from Kremnica will the passenger car reach truck, and when?
• Slow saving in banks How long will it take to save € 9,000 by depositing € 200 at the beginning of each year at 2% interest?
• Soldier An experienced soldier digs a good trench in 30 hours. Two soldiers dug the same trench each 40 hours. How many hours will the ditch dig all three together?

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