Mo has 6 identical pairs of black shoes, 7 identical pairs of brown shoes and 8 identical pairs of grey shoes. She's trying to choose 2 pairs of shoes of a different color without looking. At least how many shoes should Mo take in order to do that for sure?
A.4

B.2

C.6

D.3

Given two function \(f\left(x\right)=\sqrt{25x^2-30x+9}\), \(g\left(y\right)=y\). How many values of a are there such that \(f\left(a\right)=g\left(a\right)+7\)?

Find all positive integer values of n such that \(\dfrac{n-17}{n+23}\) is a square of a quotient number.

Given two functions \(f\left(x\right)=5x+1\) and \(g\left(x\right)=ax+3\). Find the value of g(1) if \(a=f\left(2\right)-f\left(-1\right)\)

The radius of the incircle of a isosceles triangle with one side length of 4cm is...

How many values of the whole number m such that the function \(y=\left(2016-m^2\right)x+3\) is increasing?

The Ford car left Hanoi for Nghe An and the Audi car left Nghe An for Hanoi at the same time. The ratio of their speed (the Ford car to the Audi car) was 4:3.The Ford decreased its speed by 25% and the Audi car increased its speed by 25% after they had passed each other. When the Ford car reached Nghe An, the Audi car was still 20km away from Hanoi. The distance between Hanoi and Nghe An is...

Given \(A=\left(x-2y\right)^2+\left(x-3\right)^2+\left(y-1\right)^2+3\). The least possible value of A is:...

Given a polynomial f(x) such that \(x^3+2x^2\left(4y-1\right)-4xy^2-f\left(x\right)=-5^3+4xy\left(2x-y\right)\). The value of \(f\left(\dfrac{f\left(-5\right)}{5^2}\right)\)=...

How many liters of a 92 - octane gasoline should be mixed with 200 liters of a 98 - octane gasoline to produce a mixture that is 96 - octane gasoline.

The sum of all solutions of the equation \(\left|2x+|x-3|\right|=2\) is:...

The value of x + y satisfying the sequence 1 ; -2 ; -5 ; 5 ; -8 ; 7 ; x ; y

The sum of all posible natural numbers n such that n² + n +1589 is a perfect square is

The value fo x + y satisfyng the sequence 1 ; -2 ; -5 ; 5 ; -8 ; 7 ; x ; y

\(\dfrac{\left(4\times7+2\right)\left(6\times6+2\right)\left(8\times11+2\right)\cdot\cdot\cdot\left(100\times103+2\right)}{\left(5\times8+2\right)\left(7\times10+2\right)\left(9\times12+2\right)\cdot\cdot\cdot\left(99\times102+2\right)}=...\)

A rectangle has length p cm and breadth q cm, where p and q are integers and p and q satisfy the equation pq + q = 13 + q² then the maximum possible area of the rectangle is...

Given triangle ABC with AH = 8 cm, BC = 20 cm. The area of the triangle ADE is ... cm²

A triangle ABC has \(\widehat{A}=120^o\) and the bisector AD \(\left(D\in BC\right)\). If AB = 40 cm, AD = 30 cm then AC = ...

Given \(f\left(x\right)=\dfrac{2x^2+3x+3}{2x-1}\). If a and f (a) are both integers, we say that f (a) is an element of the set A. What is the sum of all elements of the set A?

The triangle ABC has AB = 24 cm. If D is on the line segment AC such that \(\widehat{ABC}=\widehat{BDC}\), AD = 7 cm, DC = 9 cm. The measure of BD?