Question

Dunya wants to open an umbrella store. She already has some umbrellas, but needs to buy more. She starts to buy 9 umbrellas every week. After 15 weeks, she has 168 umbrellas. How many umbrellas did she start with?​

Answer 1

• 33 umbrellas

Task :

• To work out the number of umbrellas Dunya started with

Solution :

• Number of umbrellas she buy every week : 9
• Number of umbrellas she has after 15 weeks : 168

From the information above, we can acquire that when the number of umbrellas Dunya started with gets added to 9 multiplied by 15 weeks, we get 168 umbrellas ,so in order to find out the initial number of umbrellas,we can write the information as a function considering the umbrellas as ,'u'.

• 
  `u + 9(15) = 168`
• 
  `u + 135 = 168`
• 
  `u = 168 - 135`
• 
  `u = 33`

Thus, the number of umbrellas that Dunya started with is 33 .

Answer 2

33 umbrellas

Explanation:

let

• Total number of umbrella be t .
• Starting number of umbrella be s.
• Number of umbrellas bought be n.

In order to solve this problem, we can use the following equation:t = s + n

We know that Dunya has 168 umbrellas after 15 weeks, and she buys 9 umbrellas every week.

We have total number of umbrellas bought (t) = 168 umbrellas.

So, we can calculate the number of umbrellas(n) she bought as follows:

n = 15 weeks × 9 umbrellas/week

= 135 umbrellas

Now, we can substitute these values into the original equation to find the starting number of umbrellas(s):

t = s + n

168 = s + 135

Isolate s.

s = 168 - 135

s = 33

So,

Starting number of umbrellas = 33 umbrellas

Therefore, Dunya had 33 umbrellas at the start.