Answer:
Katherine need to work minimum 10 hours lifeguarding to meet her requirements
Explanation:
Given:
Rate for Lifeguarding =

Rate for walking dogs =

She had worked 2 hours walking dog
Money for walking dogs = Rate for walking dogs
hours worked=

she can work a maximum of 15 total hours and must earn at least $160.
Let hours required for lifeguarding be x
Money for life guarding = Rate for walking dogs
hours worked for lifrguarding=

Total Money she must earn = Money for lifeguarding + Money for walking dogs

Rounding to nearest hour
Katherine need to work minimum 10 hours lifeguarding to meet her requirements