Linear functions

9000007209

Level: 
C
A current-voltage characteristics is shown in the graph. Find the current \(I\) as a function of the voltage \(U\).
\(I = \frac{2} {3}U -\frac{4}{3};U\in [2;\infty) \)
\(I = \frac{3} {2}U - 2;U\in [2;\infty) \)
\(I = \frac{3} {2}U + 2;U\in [2;\infty) \)
\(I = \frac{2} {3}U + 2;U\in [2;\infty) \)

9000007808

Level: 
B
Given a function \(f(x) = \frac{x} {3} + 1\), find the function \(g\) such that the graph of \(g\) is symmetric with the graph of \(f\) about the \(y\)-axis.
\(g\colon y = -\frac{x} {3} + 1\)
\(g\colon y = 3x + 1\)
\(g\colon y = -3x + 1\)
\(g\colon y = -\frac{x} {3} - 1\)
Such a function does not exist.

9000007809

Level: 
C
The price of a goods in a shop is \(\$15\) per item. The Internet price in an e-shop is cheaper by \(\$2\) per item. The shipping cost of the e-shop is \(\$125\). What is the minimal number of items, which makes the total cost for a transaction smaller in the e-shop?
\(63\)
\(9\)
\(62\)
\(125\)
\(126\)

9000007810

Level: 
C
A fuel tank in a car has the capacity \(40\) litres. The current volume of the fuel in the fuel tank is \(6\) litres. The speed of fuelling is \(1\) litre of gasoline each \(3\) seconds. Find the function which describes the volume of the gasoline in the fuel tank (in litres) as a function of time (in seconds).
\(V = \frac{1} {3}t + 6,\ t\in [ 0;102] \)
\(V = 3t + 6,\ t\in [ 0;102] \)
\(V = 3t + 6,\ t\in [ 0;40] \)
\(V = 3t + 6,\ t\in \mathbb{R}_{0}^{+}\)
\(V = \frac{1} {3}t + 6,\ t\in [ 0;40] \)