There are n sweets in a bag. 6 of the sweets are orange. The rest of the sweets are yellow. Hannah takes a sweet from the bag and eats it. Hannah then takes at another sweet. The probability that Hannah eats two orange sweets is 1/3. Show that n²-n-90=0

P(2 orange sweets) = P(orange sweet) * P(orange sweet)

(6/n) * (5/(n-1)) = 1/3

30/(n(n-1)) = 1/3

90 = n(n-1)

90 = n2-n

n2-n-90=0 as required

Answered by Tim V. Maths tutor

15216 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

A shape consists of a quarter circle (radius r = 4cm) attached to a triangle (side length = 4cm and hypotenuse = 5cm). This shape is surrounded by a square (side length 8cm). If the shape is coloured in, what is the area in the square that is uncoloured?


Factorise 5a – 3a^2


Expand 5(2x-6)


Solve: sin(x) = 0.5, in the interval of 0 < x < 360 degree.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences