Sajjad1994
Over a seven-year period, from 2002 to 2009, the number of babies born to married couples increased despite a decrease in marriages from 17,000 marriages in 2002.
In the given expression, B and M represent the percent change in the babies and marriages, respectively. I represents the number of babies per married couple in 2002. The percent change in a quantity is calculated by the formula:
\((\frac{X_{new}-X_{old}}{X_{old}})*100\)
In the table below select for (I) The expression that represents the number of babies born in 2002 and (II) The expression of the number of babies born per family in 2009. Select one value in each column.
(I) The number of babies born in 2002 equals the number of marriages that year multiplied by the number of babies per marriage. Since there were 17,000 marriages and the average was I babies per marriage, the total number of babies born in 2002 is \(17000 * I\).
(II) To find the number of babies born per family in 2009, we need to consider how both the total number of babies and the total number of marriages changed over time.
- The number of babies increased by B%, so the total number of babies in 2009 is \(17000 * I * \frac{100 + B}{100}\).
- The number of marriages changed by M%, so the number of marriages in 2009 is \(17000 * \frac{100 + M}{100}\).
The number of babies per family in 2009 is therefore:
\(\frac{17000 * I * \frac{100 + B}{100}}{17000 * \frac{100 + M}{100}}\)
The 17000 and 100 terms cancel out, leaving:
\(\frac{100 + B}{100 + M} * I\)