Question

1 jenny was told to think of a number, treble it, and then add 15. the result was greater than 60.
find the possible values of jennys original number.
2 as part of a special promotion, a furniture store is offering customers the choice of either $60 off
or else 15% off the purchase price.
determine the purchase prices for which customers would be better off choosing the 15% discount.
3 the cost of sending a parcel depends on its weight. the amounts charged by two delivery services
are:
swift delivery:
$8 flat fee plus $1.30 per kg
lightning pace:
$6 flat fee plus $1.50 per kg

Explanation:

Step1: Set up the inequality

Let the original number be \(x\). Treble it gives \(3x\), then add \(15\) gives \(3x + 15\). Since the result is greater than \(60\), we have the inequality \(3x+15>60\).

Step2: Solve the inequality

Subtract \(15\) from both sides: \(3x+15 - 15>60 - 15\), which simplifies to \(3x>45\).
Divide both sides by \(3\): \(\frac{3x}{3}>\frac{45}{3}\), so \(x > 15\).

Answer:

The original number \(x\) is greater than \(15\), i.e., \(x\in(15,\infty)\)