diff --git a/tasks/task2.ipynb b/tasks/task2.ipynb
index 74d7413..16ddabd 100644
--- a/tasks/task2.ipynb
+++ b/tasks/task2.ipynb
@@ -14,7 +14,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": 2,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -32,7 +32,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": 3,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -57,7 +57,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": 4,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -91,7 +91,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": 5,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -136,7 +136,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 5,
+   "execution_count": 6,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -188,7 +188,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 6,
+   "execution_count": 7,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -217,7 +217,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 7,
+   "execution_count": 8,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -251,7 +251,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 8,
+   "execution_count": 9,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -266,7 +266,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 9,
+   "execution_count": 10,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -292,7 +292,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 10,
+   "execution_count": 11,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -317,7 +317,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 11,
+   "execution_count": 12,
    "metadata": {},
    "outputs": [
     {
@@ -329,14 +329,14 @@
       "Defining source terms\n",
       "Defining boundary conditions\n",
       "Time stepping...\n",
-      "0.6 %        3.1e+00 s    Ellapsed time so far: 0.4 s\r"
+      "0.2 %        1.0e+00 s    Ellapsed time so far: 0.3 s\r"
      ]
     },
     {
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "100.0 %        5.0e+02 s    Ellapsed time so far: 13.5 s\n"
+      "100.0 %        5.0e+02 s    Ellapsed time so far: 22.3 s\n"
      ]
     }
    ],
@@ -347,7 +347,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 12,
+   "execution_count": 13,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -360,7 +360,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 13,
+   "execution_count": 14,
    "metadata": {},
    "outputs": [
     {
@@ -369,7 +369,7 @@
        "Text(0.5, 0, 'Time (s)')"
       ]
      },
-     "execution_count": 13,
+     "execution_count": 14,
      "metadata": {},
      "output_type": "execute_result"
     },
@@ -402,7 +402,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 14,
+   "execution_count": 15,
    "metadata": {},
    "outputs": [],
    "source": [
@@ -425,7 +425,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 15,
+   "execution_count": 16,
    "metadata": {},
    "outputs": [
     {
@@ -434,7 +434,7 @@
        "Text(0.5, 0, 'Time (s)')"
       ]
      },
-     "execution_count": 15,
+     "execution_count": 16,
      "metadata": {},
      "output_type": "execute_result"
     },
@@ -474,7 +474,30 @@
    "source": [
     "### Task:\n",
     "1) Increase the implantation temperature to 500 K and see how the TDS spectrum is affected\n",
-    "2) Vary the detrapping energy of the first trap"
+    "2) Vary the detrapping energy of the first trap\n",
+    "3) At the end of the implantation phase, what is the proportion of hydrogen trapped in trap 2?\n",
+    "\n",
+    "    <details>\n",
+    "    <summary>Show solution</summary>\n",
+    "    <br>\n",
+    "    Make use of the exported derived quantities.\n",
+    "\n",
+    "    We computed the hydrogen inventory in traps 1, 2 and 3 as well as the mobile inventory.\n",
+    "\n",
+    "    ```python\n",
+    "    t = derived_quantities.t\n",
+    "    trap_1 = derived_quantities.filter(fields=\"1\").data\n",
+    "    trap_2 = derived_quantities.filter(fields=\"2\").data\n",
+    "    trap_3 = derived_quantities.filter(fields=\"3\").data\n",
+    "    mobile = derived_quantities.filter(fields=\"solute\", instances=F.TotalVolume).data\n",
+    "    total = derived_quantities.filter(fields=\"retention\").data\n",
+    "\n",
+    "    plt.stackplot(t, trap_1, trap_2, trap_3, mobile)\n",
+    "    ```\n",
+    "\n",
+    "    Try to run it!\n",
+    "\n",
+    "    </details>\n"
    ]
   }
  ],