please can somebody explain to me how to do this questions

8. Elli travelled 700km by truck to deliver some ostriches to her friend's farm. she then returned the same distance by car. The car averaged 10km/h faster than the truck and took 1 hour less time. What was the speed of the car?

9. When two pumps are turned on they can fill the pond at Cassandra's farm in seven hours. individually, one pump takes two hours longer than the other to fill the pond. Find the time to fill the pond by the faster pump by itself.

10. A boat travelled 30km upstream, against the current, to deliver some feed from Elli, to Helmut's farm, it then turned around and headed 35km downstream to dock for the night. If the speed of the current was 3km/h and the upstream trip took 45 mins longer than the downstream trip, what was the speed of the boat?

this unit is about solving quadratics with the quadratic formula

  1. 👍
  2. 👎
  3. 👁
  1. If the car's speed was s, then the truck's speed was s-10.
    Since time = distance/speed, and the truck took an extra hour,
    700/(s-10) = 700/s + 1
    clearing the fractions, you get
    700s = 700(s-10) + 1(s)(s-10)
    s^2 - 10s - 7000 = 0
    Now, using the quadratic formula, you have
    s = (10±√(100+28000))/2 = 5±√7025 = 5(1±√281)
    You want the positive value.

    For the pumps, you have the usual work problem, so you have
    1/x + 1/(x+2) = 1/7

    #10 is pretty much like #8. How far do you get on it?

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. Math(Factorial)

    A women student is to answer 10 out of 13 questions on a test. Find the number of choices where she must answer: (a) the first two questions; (b) the first or second questions but not both; (c) exactly 3 out of the first 5

  2. math

    can someone please answer these questions for me?: 1. if the measure of an interior angle of a regular pentagonis 108 degrees, then the angle sum of that regular pentagon must be: A. 120 degrees B. 360 degrees C. 540 degrees D.

  3. physics

    A cage descends a mine shaft with an acceleration of 0.5 m/s2. After the cage has travelled 25 metres, a stone is dropped from the top of the shaft. Determine : 1. the time taken by the stone to hit the cage, and 2. distance

  4. Maths

    Two boats A and B left a port C at the same time on different route .B travelled on a bearing of 150 degree and A travelled 8km and B had travelled 10km ,the distance between the Two boats was found to be 12km .calculate the

  1. AP Calculus AB

    For an object whose velocity in ft/sec is given by v(t) = -t^2 + 6, what is its displacement, in feet, on the interval t = 0 to t = 6 secs? -36 36 0 55.596 For an object whose velocity in ft/sec is given by v(t) = -2t^2 + 4, what

  2. Science

    If anyone could check my work on these science questions that'd be great, thank you! 1. Which statement describes metamorphic rock formation? A. Layers build up over time *** B. Magma cools and hardens. C. Once-living organisms

  3. Math

    Two ships A and B leaves the some harbour at the same time in directions 152° and 142° respectively calculate the distance between the two ships when A has travelled 10km and B has travelled 12km. What is the bearing of A from B

  4. Math

    A basketball is tossed from the top of a 3m wall. The path of the basketball is defined by the relation y=-x^2+2x+3 where x represent the horizontal distance travelled, in metres, and y represents the height, in metres, above the

  1. maths

    the equation for the motion of an object with constant acceleration is d=vt+0.5at^2where d is the distance travelled in ft, v is the starting velocity in ft/s a is the acceleration in ft/s^2 and t is time in seconds a race car

  2. math homework

    two boats A and B left a port C at the same time on different routes. B travelled on a bearing of 150 and A travelled on the north side of B. When A had travelled 8km and the two boats was found to be 12km. Calculate the bearing

  3. math

    The total distance from Timothy's house to school was 9.18 km.He travelled by bus for part of the journey and walked the rest of the way.The distance he walked was 7.95 km less than the distance he travelled by bus.How far did

  4. math

    Speed is determined by dividing the distance travelled by the time taken to travel the distance or s= d/t. Write a rational expression for speed, given the distance travelled, is 3p^2+5p-2 and the time to travel that distance is

You can view more similar questions or ask a new question.