A certain type of computer is given a 10% discount promotion, and each computer can still earn a profit of 120 yuan; it is known that the purchase price of each computer is 4200 yuan, what is the original price of this type of computer.
某种型号的电脑打九折促销，每台仍可获得利润120元；已知每台电脑的进价是4200元，则这种型号的电脑原来售价是多少元．
<gadget id="calculator">120 + 4_200</gadget>
<output>4_320</output>

<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">4_320 / (9/10)</gadget>
<output>4_800</output>

<result>4_800</result>