Step-by-step explanation: Lets estimate first to the nearest whole number.
15.8 kilograms estimated is 16 kg
17.42 kilograms estimated is 17 kg
16.28 kilograms estimated is 16 kg
Now add the estimated values, 16 + 17 + 16 = 49 kg
The estimate gives you the correct answer because it gives you an accurate reasonable amount in this problem.
Answer:
74
Step-by-step explanation:

Keep in mind units and it will make sense
20(34)(4*6) = ?
Answer:
After 4 days, the number of people attending both conferences be the same.
Step-by-step explanation:
We are given the following in the question:
Maths conference:
Number of people already signed = 7
Number of people who sign up each day = 2
Thus, the number of people who will sign up for maths conference in x days will be given by the linear function:

History conference:
Number of people already signed =11
Number of people who sign up each day = 1
Thus, the number of people who will sign up for maths conference in x days will be given by the linear function:

Both conference will have same number of people when

Thus, after 4 days, the number of people attending both conferences be the same.