R S Aggarwal Solutions for Chapter: Linear Equations in One Variable, Exercise 4: TEST PAPER-9

The cost of $1$ pen is $₹16$ and the cost of $1$ pencil is $₹5$. If the total cost of $x$ pens and $y$ pencils is $₹\left(\mathrm{m}x+\mathrm{n}y\right)$, then find the value of $\mathrm{m}+\mathrm{n}.$

Lalit earns $₹x$ per day and spends $₹y$ per day. How much does he save in $30$ days?

Three times a number added to $8$ gives $20.$ Find the number.

If $x=1, y=2$ and $z=3$, find the value of $x^2+y^2+2xyz.$

Find the value of $x$ if $4x+9=17$.

Solve the equation and find the value of $x$: $3(x+2)-2(x -1)=7$

Solve and find the value of $x$: $\frac{2x}{5}-\frac{x}{2}=\frac{5}{2}$

After $16$ years, Seema will be three times as old as she is now. If her present age is $k$ years, find $k$.