need help 4 a complicated math question!!!!!!!!!!!!!!!!!!

yuanjolly

Beth’s pizzeria offers x different toppings.  What is the value of x?

(1)    There are an equal number of different pizzas that can be made with (x ? 2) toppings as there are different pizzas with just 2 toppings.

(2)    If the pizzeria were to add one additional topping, the number of different pizzas that could be made with 4 toppings would double.


thanks in advance!!!!!!!!!!

yuanjolly

the answer is B

yuanjolly

come on,,,someone gives a tip or sth`````````````the question lies on the smart knowledge of wat it asks 4``but i cannot figure it out``or in temporary confusion of the question`

rachelapple

就是组合问题

B 如果多加一种Topping 那么任选4种topping的pizza的数目会多一倍

则：Cx/4(4在上面）=2C(x-1)/4(4在上面）
解：x=8

A 是说如果能有x-2种topping的pizza和能有2种topping的pizza一样多 根据组合的规律 x有无数解

yuanjolly

lol```got it````i kno itz a simple one but cannot figure out how to translate it, u seem to clearly kno the nature of the question. thanks a lot, u b very helpful````
for (1), it is a little of confusion. but itz clear for (2), and from formula of (2) u gave, i am sort of understanding the nature of the question..........................

rachelapple

客气 组合的一个规律就是Cn/k = Cn/(n-k) 无论n取任何值 k和n-k种的组合数都一样多

fly12404

(1)    There are an equal number of different pizzas that can be made with (x ? 2) toppings as there are different pizzas with just 2 toppings.
可以解釋A的意思嗎
不大懂

yuanjolly

jesus```finally, got the whole picture of the question, it is to test the nature of the combination~~~~~~~and simply translate it into a specific question with a daily context~~~~~~wat a GMAC

yuanjolly

i think (1) means the combination numbers of both 2 and x-2 are the same, this correlates with the nature of what the nice guy said........and u can figure it out by refering 2 the man's say`````

fly12404

are U have OA of this question?
Is that B??