To calculate the cost of the telegram with 13 words, you need to consider the base cost of 10 words and the additional cost for the remaining 3 words.
Let's break it down step by step:
1. Calculate the base cost for 10 words:
The ordinary telegram costs Sh 3 for 10 words, so the cost will be Sh 3.
2. Calculate the additional cost for the remaining 3 words:
Each extra word has a charge of 30 cents. As there are 3 extra words, the additional cost will be 3 * 30 cents, which is 90 cents in total.
3. Add the base cost and the additional cost to find the total cost:
The base cost is Sh 3 and the additional cost is 90 cents (or 0.90 Sh). Therefore, the total cost will be Sh 3 + 0.90 Sh, which is Sh 3.90.
So, the cost of the telegram with 13 words will be Sh 3.90.