There are m fruits in a basket. 3 of the fruits are kiwis; the rest are lemons. The probability of picking two kiwis in a row (without replacement) is 0.3. Show m^2 - m - 20 = 0.

Number of lemons = m - 3. Construct a tree diagram using the information given to represent picking two fruits out of the basket (without replacement) one after the other. Since picking each fruit is an independent event, just multiply probabilities to find the probability of selecting a kiwifruit twice in a row: P(two kiwifruits in a row) = 3/m * 2/(m - 1) and set this equal to 0.3 (given in the question). A bit of rearrangement of the algebra gives: 3/10 = 6/[m(m - 1)] => 3m(m - 1) = 60 => m(m - 1) = 20 => m2 - m - 20 = 0 as required.

HW
Answered by Heather W. Maths tutor

2374 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Bob buys a car for £120 after it is reduced by 20% in the sale. What was the original price of the car?


Solve the following simulateous equations: 3x+y=11 and 2x+y=8


A book was reduced by 35% in a sale. It's new price is £16. What was the original price ?


How do I work out the area of a quarter circle with radius 6cm?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences