In a box, there is 1 more green pens than black pens. The probability of taking 2 black pens is 0.2 . How many pens are in the box?

g = b+8g+b = p = 2b+1(b/p) x (b-1)/(p-1) = 1/5(b^2 - b)/(p^2 - p) = 1/5sub in p= 2b+1(b^2 - b)/(4b^2 + 2b) = 1/55b^2 - 5b = 4b^2 + 2bb^2 -7b = 0b = 7 or b = 0 (cannot be 0 as 2 pens must be taken)p = 2(7) + 1 = 15 pens

JL
Answered by James L. Maths tutor

2944 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

How do I factorise a quadratic equation?


In a bag of 72 red and green marbles, 5/9 are green. What is the number of red marbles in the bag?


x^2+2=18, find the value of x.


How do you rearrange x = (2y+1)/(3y+4) to get y in terms of x?


We're here to help

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

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning