Rob is saving to buy a new mp3 player. for every $15 he earns babysitting, he saved $6.on sunday, rob earned $75 babysitting. how much money did he save?

Ok so first of all, Why does rob need a mp3 player? we are in the new age, right?

Secondly, I will answer your question :P

Ok so we have some info here .... we know that Rob earns $15 and saves $6

We can assume that Rob earning's equation would be y = 15x-6x

We are also given that he earned $75 (My gosh Rob nice work man!)

we would plug in 75 for y >>>for now forget the fact that Rob saves<<<

Divide 75 by 15 which = 5

Now multiply 6 by 5 which = 30 (AnSWERR!)

We now also know that out of what Rob earned he used or donated to charity $75-30 = $ 45

We can double check our work here real quick

what

y= 2x+7

changed to y= 5x +7

as slope is increased from 2 to 5

therefore it would be less steeper

so, option d) is correct