A, B, and C weigh 450 kg in total. The mass ratio of A to B is 5:4, and the mass ratio of B to C is 2:3. How much does A weigh?
甲、乙、丙三种物品共重450千克，甲与乙的质量比是5：4，乙与丙的质量比是2：3，甲物品重多少千克？
<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(5/4) + 1 + (3/2)</gadget>
<output>15/4 = around 3.75</output>

<gadget id="calculator">450 / (15/4)</gadget>
<output>120</output>

<gadget id="calculator">120 * (5/4)</gadget>
<output>150</output>

<result>150</result>