



 
Hi Abdi. Let s = the speed of the car and t = the time it takes to drive 175 miles. Then 175/s = t. If the speed was 20 mph faster (that's s + 20), then the time would be one hour less (that's t  1) So 175 / (s + 20) = t  1. This gives you two equations with two unknowns, so you can solve it from here. Look up simultaneous equations in our Quick Search if you need more help. Cheers,  


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