Final answer:
The cost of 10 packages of pens is $17.50, and the cost of 1 package of pens is $1.75.
Step-by-step explanation:
To calculate the cost of p packages of pens, Rana uses the formula 1.75p. To find the cost of 10 packages of pens, we can substitute p with 10 in the formula. So, the cost of 10 packages of pens is: 1.75 x 10 = $17.50. Similarly, to find the cost of 1 package of pens, we can substitute p with 1 in the formula. So, the cost of 1 package of pens is: 1.75 x 1 = $1.75.