Solution with concentration of both cell and water same
water enters in the cell from both directions and get into it 
it applies force on the cell wall and equal force is applied by the cell wall so no change in size of cell niether it swells nor it shrinks.such type of solution is known as isotonic solution
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Isotonic solution: A solution that has the same salt concentration as cells and blood. Isotonic solutions are commonly used as intravenously infused fluids in hospitalized patients.