Ling has m dolls. Alice has 3 times as many doll's as Long. Betty has 7 fewer doll's than Alice. How many dolls do they have in all. Give your answer in terms of m

Answer 1

To answer this question, we are going to need to sum up how many dolls Ling, Alice, and Betty have. So, let's start by determining how many dolls they each have and then we can add them all together.

Remember, our answer needs to be in terms of m, so it is not important for us to determine the exact number of dolls Ling has. We just need to know that she has m dolls.

Ling: m dolls

Now, Alice has 3 times as many dolls as Ling. So, to determine how many dolls Alice has, we are going to count the number of dolls Ling has 3 times, or in other words multiply the number of dolls Ling has by 3. Since Ling has m dolls, Alice has 3 times m, or 3m.

Alice: 3m dolls

Next, we'll determine how many dolls Betty has. Betty has 7 fewer dolls than Alice. So, to determine how many dolls Betty has, we are going to subtract 7 from the number of dolls Alice has. Since Alice has 3m dolls, Betty has 7 less than 3m, or 3m – 7.

Betty: 3m – 7

Finally, we can add up the number of dolls each of the girls has to find out how many dolls they have in total. Since we kept our previous work in terms of m, our answer will be in terms of m as well.

Ling + Alice + Betty = m + 3m + (3m – 7)

= m + 3m + 3m – 7

= 7m – 7

So, in all, the girls have 7m – 7 dolls.