There are n n\,n sweets in a jar.
3 of the sweets are yellow and the rest are pink.
Leo takes a sweet from the jar at random and eats it. He then takes another sweet at random from the jar.
The probability that Leo takes two pink sweets is 715\displaystyle \frac{7}{15}157
Show that 4n2−49n+90=04n^2 - 49n + 90 = 04n2−49n+90=0
Find the value of nnn.